diff --git a/infra/db/converter.go b/infra/db/converter.go
index 59b142e..99a2c5b 100644
--- a/infra/db/converter.go
+++ b/infra/db/converter.go
@@ -15,16 +15,17 @@ func ConvCreateRoomParamsToRoom(src CreateRoomParams) (dst Room) {
 	dst.Place = src.WriteRoomParams.Place
 	dst.TimeStart = src.WriteRoomParams.TimeStart
 	dst.TimeEnd = src.WriteRoomParams.TimeEnd
-	dst.Admins = make([]RoomAdmin, len(src.WriteRoomParams.Admins))
+	dst.Admins = make([]User, len(src.WriteRoomParams.Admins))
 	for i := range src.WriteRoomParams.Admins {
-		dst.Admins[i] = convuuidUUIDToRoomAdmin(src.WriteRoomParams.Admins[i])
+		dst.Admins[i] = ConvuuidUUIDToUserMeta(src.WriteRoomParams.Admins[i])
 	}
 	return
 }
-func ConvEventAdminToRoomAdmin(src EventAdmin) (dst RoomAdmin) {
-	dst.UserID = src.UserID
-	return
-}
+
+// func ConvEventAdminToRoomAdmin(src EventAdmin) (dst RoomAdmin) {
+// 	dst.UserID = src.UserID
+// 	return
+// }
 
 func ConvEventAdminTodomainUser(src EventAdmin) (dst domain.User) {
 	dst.ID = src.UserID
@@ -100,10 +101,10 @@ func ConvGroupTodomainGroup(src Group) (dst domain.Group) {
 	(*dst.Model.DeletedAt) = convgormDeletedAtTotimeTime(src.Model.DeletedAt)
 	return
 }
-func ConvRoomAdminTodomainUser(src RoomAdmin) (dst domain.User) {
-	dst.ID = src.UserID
-	return
-}
+// func ConvRoomAdminTodomainUser(src RoomAdmin) (dst domain.User) {
+// 	dst.ID = src.UserID
+// 	return
+// }
 
 func ConvRoomTodomainRoom(src Room) (dst domain.Room) {
 	dst.ID = src.ID
@@ -117,7 +118,7 @@ func ConvRoomTodomainRoom(src Room) (dst domain.Room) {
 	}
 	dst.Admins = make([]domain.User, len(src.Admins))
 	for i := range src.Admins {
-		dst.Admins[i] = convRoomAdminTodomainUser(src.Admins[i])
+		dst.Admins[i] = convUserTodomainUser(src.Admins[i])
 	}
 	dst.CreatedBy = convUserTodomainUser(src.CreatedBy)
 	dst.Model.CreatedAt = src.Model.CreatedAt
@@ -127,10 +128,18 @@ func ConvRoomTodomainRoom(src Room) (dst domain.Room) {
 	return
 }
 
-func ConvSEventAdminToSRoomAdmin(src []EventAdmin) (dst []RoomAdmin) {
-	dst = make([]RoomAdmin, len(src))
+// func ConvSEventAdminToSRoomAdmin(src []EventAdmin) (dst []RoomAdmin) {
+// 	dst = make([]RoomAdmin, len(src))
+// 	for i := range src {
+// 		dst[i] = convEventAdminToRoomAdmin(src[i])
+// 	}
+// 	return
+// }
+
+func ConvSEventAdminToSUser(src []EventAdmin) (dst []User) {
+	dst = make([]User, len(src))
 	for i := range src {
-		dst[i] = convEventAdminToRoomAdmin(src[i])
+		dst[i] = convEventAdminToUser(src[i])
 	}
 	return
 }
@@ -207,9 +216,9 @@ func ConvUpdateRoomParamsToRoom(src UpdateRoomParams) (dst Room) {
 	dst.Place = src.WriteRoomParams.Place
 	dst.TimeStart = src.WriteRoomParams.TimeStart
 	dst.TimeEnd = src.WriteRoomParams.TimeEnd
-	dst.Admins = make([]RoomAdmin, len(src.WriteRoomParams.Admins))
+	dst.Admins = make([]User, len(src.WriteRoomParams.Admins))
 	for i := range src.WriteRoomParams.Admins {
-		dst.Admins[i] = convuuidUUIDToRoomAdmin(src.WriteRoomParams.Admins[i])
+		dst.Admins[i] = ConvuuidUUIDToUserMeta(src.WriteRoomParams.Admins[i])
 	}
 	return
 }
@@ -288,21 +297,26 @@ func ConvuuidUUIDToGroupMember(src uuid.UUID) (dst GroupMember) {
 	dst.UserID = src
 	return
 }
-func ConvuuidUUIDToRoomAdmin(src uuid.UUID) (dst RoomAdmin) {
-	dst.UserID = src
-	return
-}
+// func ConvuuidUUIDToRoomAdmin(src uuid.UUID) (dst RoomAdmin) {
+// 	dst.UserID = src
+// 	return
+// }
 func ConvuuidUUIDToUserMeta(src uuid.UUID) (dst User) {
 	dst.ID = src
 	return
 }
 
-func convEventAdminToRoomAdmin(src EventAdmin) (dst RoomAdmin) {
-	dst.UserID = src.UserID
+// func convEventAdminToRoomAdmin(src EventAdmin) (dst RoomAdmin) {
+// 	dst.UserID = src.UserID
+// 	return
+// }
+
+func convEventAdminTodomainUser(src EventAdmin) (dst domain.User) {
+	dst.ID = src.UserID
 	return
 }
 
-func convEventAdminTodomainUser(src EventAdmin) (dst domain.User) {
+func convEventAdminToUser(src EventAdmin) (dst User) {
 	dst.ID = src.UserID
 	return
 }
@@ -375,10 +389,10 @@ func convGroupTodomainGroup(src Group) (dst domain.Group) {
 	(*dst.Model.DeletedAt) = convgormDeletedAtTotimeTime(src.Model.DeletedAt)
 	return
 }
-func convRoomAdminTodomainUser(src RoomAdmin) (dst domain.User) {
-	dst.ID = src.UserID
-	return
-}
+// func convRoomAdminTodomainUser(src RoomAdmin) (dst domain.User) {
+// 	dst.ID = src.UserID
+// 	return
+// }
 func convRoomTodomainRoom(src Room) (dst domain.Room) {
 	dst.ID = src.ID
 	dst.Place = src.Place
@@ -391,7 +405,7 @@ func convRoomTodomainRoom(src Room) (dst domain.Room) {
 	}
 	dst.Admins = make([]domain.User, len(src.Admins))
 	for i := range src.Admins {
-		dst.Admins[i] = convRoomAdminTodomainUser(src.Admins[i])
+		dst.Admins[i] = convUserTodomainUser(src.Admins[i])
 	}
 	dst.CreatedBy = convUserTodomainUser(src.CreatedBy)
 	dst.Model.CreatedAt = src.Model.CreatedAt
@@ -439,7 +453,7 @@ func convuuidUUIDToGroupMember(src uuid.UUID) (dst GroupMember) {
 	return
 }
 
-func convuuidUUIDToRoomAdmin(src uuid.UUID) (dst RoomAdmin) {
-	dst.UserID = src
-	return
-}
+// func convuuidUUIDToRoomAdmin(src uuid.UUID) (dst RoomAdmin) {
+// 	dst.UserID = src
+// 	return
+// }
diff --git a/infra/db/hooks.go b/infra/db/hooks.go
index 078c57f..3c7f6ff 100644
--- a/infra/db/hooks.go
+++ b/infra/db/hooks.go
@@ -22,7 +22,7 @@ func (e *Event) BeforeSave(tx *gorm.DB) (err error) {
 			e.Room.TimeStart = e.TimeStart
 			e.Room.TimeEnd = e.TimeEnd
 			e.Room.CreatedByRefer = e.CreatedByRefer
-			e.Room.Admins = ConvSEventAdminToSRoomAdmin(e.Admins)
+			e.Room.Admins = ConvSEventAdminToSUser(e.Admins)
 		} else {
 			return NewValueError(ErrRoomUndefined, "roomID", "place")
 		}
@@ -180,8 +180,7 @@ func (r *Room) BeforeSave(tx *gorm.DB) (err error) {
 }
 
 func (r *Room) BeforeUpdate(tx *gorm.DB) (err error) {
-	err = tx.Where("room_id", r.ID).Delete(&RoomAdmin{}).Error
-	if err != nil {
+	if err := tx.Model(r).Association("Admins").Clear(); err != nil {
 		return err
 	}
 	return nil
diff --git a/infra/db/model.go b/infra/db/model.go
index 90cb213..5bd8e01 100644
--- a/infra/db/model.go
+++ b/infra/db/model.go
@@ -15,7 +15,7 @@ var tables = []interface{}{
 	GroupAdmin{},
 	Tag{},
 	Room{},
-	RoomAdmin{},
+	// RoomAdmin{},
 	Event{},
 	EventTag{}, // Eventより下にないと、overrideされる
 	EventAdmin{},
@@ -79,12 +79,12 @@ type UserBody struct {
 	User        User `gorm:"->; foreignKey:ID; constraint:OnDelete:CASCADE;" cvt:"->"`
 }
 
-type RoomAdmin struct {
-	UserID uuid.UUID `gorm:"type:char(36); primaryKey"`
-	RoomID uuid.UUID `gorm:"type:char(36); primaryKey"`
-	User   User      `gorm:"->; foreignKey:UserID; constraint:OnDelete:CASCADE;" cvt:"->"`
-	Model  `cvt:"-"`
-}
+// type RoomAdmin struct {
+// 	UserID uuid.UUID `gorm:"type:char(36); primaryKey"`
+// 	RoomID uuid.UUID `gorm:"type:char(36); primaryKey"`
+// 	User   User      `gorm:"->; foreignKey:UserID; constraint:OnDelete:CASCADE;" cvt:"->"`
+// 	Model  `cvt:"-"`
+// }
 
 //go:generate go run github.com/fuji8/gotypeconverter/cmd/gotypeconverter@latest -s Room -d domain.Room -o converter.go .
 //go:generate go run github.com/fuji8/gotypeconverter/cmd/gotypeconverter@latest -s []*Room -d []*domain.Room -o converter.go .
@@ -95,7 +95,7 @@ type Room struct {
 	TimeStart      time.Time `gorm:"type:DATETIME; index"`
 	TimeEnd        time.Time `gorm:"type:DATETIME; index"`
 	Events         []Event   `gorm:"->; constraint:-"` // readOnly
-	Admins         []RoomAdmin
+	Admins         []User    `gorm:"many2many:room_admin_users;"`
 	CreatedByRefer uuid.UUID `gorm:"type:char(36);" cvt:"CreatedBy, <-"`
 	CreatedBy      User      `gorm:"->; foreignKey:CreatedByRefer; constraint:OnDelete:CASCADE;" cvt:"->"`
 	Model          `cvt:"->"`
diff --git a/migration/current.go b/migration/current.go
index f066004..e9488bc 100644
--- a/migration/current.go
+++ b/migration/current.go
@@ -20,5 +20,6 @@ func Migrations() []*gormigrate.Migration {
 		v11(),
 		v12(),
 		v13(),
+		v14(),
 	}
 }
diff --git a/migration/v14.go b/migration/v14.go
new file mode 100644
index 0000000..7d5b54c
--- /dev/null
+++ b/migration/v14.go
@@ -0,0 +1,78 @@
+package migration
+
+import (
+	"time"
+
+	"github.com/go-gormigrate/gormigrate/v2"
+	"github.com/gofrs/uuid"
+	"gorm.io/gorm"
+)
+
+type v14Room struct {
+	ID             uuid.UUID `gorm:"type:char(36);primaryKey"`
+	Place          string    `gorm:"type:varchar(32);"`
+	Verified       bool
+	TimeStart      time.Time `gorm:"type:DATETIME; index"`
+	TimeEnd        time.Time `gorm:"type:DATETIME; index"`
+	CreatedByRefer uuid.UUID `gorm:"type:char(36);"`
+}
+
+func (*v14Room) TableName() string {
+	return "rooms"
+}
+
+type v14RoomUser struct {
+	RoomID uuid.UUID `gorm:"type:char(36); primaryKey"`
+	UserID uuid.UUID `gorm:"type:char(36); primaryKey"`
+}
+
+func (*v14RoomUser) TableName() string {
+	return "room_admin_users"
+}
+
+type v14RoomAdmin struct {
+	UserID uuid.UUID `gorm:"type:char(36); primaryKey"`
+	RoomID uuid.UUID `gorm:"type:char(36); primaryKey"`
+}
+
+func (*v14RoomAdmin) TableName() string {
+	return "room_admins"
+}
+
+func v14() *gormigrate.Migration {
+	return &gormigrate.Migration{
+		ID: "14",
+		Migrate: func(db *gorm.DB) error {
+			// Step 1: Create the new many-to-many table
+			err := db.Migrator().CreateTable(&v14RoomUser{})
+			if err != nil {
+				return err
+			}
+
+			// Step 2: Migrate data from RoomAdmin to RoomUser
+			roomAdmins := []v14RoomAdmin{}
+			err = db.Find(&roomAdmins).Error
+			if err != nil {
+				return err
+			}
+
+			roomUsers := make([]v14RoomUser, len(roomAdmins))
+			for i, admin := range roomAdmins {
+				roomUsers[i] = v14RoomUser{
+					RoomID: admin.RoomID,
+					UserID: admin.UserID,
+				}
+			}
+
+			if len(roomUsers) > 0 {
+				err = db.Create(&roomUsers).Error
+				if err != nil {
+					return err
+				}
+			}
+
+			// Step 3: Drop the RoomAdmin table
+			return db.Migrator().DropTable(&v14RoomAdmin{})
+		},
+	}
+}