diff --git a/adapter.go b/adapter.go
index 7d5c6d0..05c0283 100644
--- a/adapter.go
+++ b/adapter.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql"
 	"fmt"
+	"runtime"
 
 	"github.com/casbin/casbin/v2/model"
 	"github.com/casbin/casbin/v2/persist"
@@ -59,6 +60,12 @@ func NewAdapter(driverName, dataSourceName string, opts ...adapterOption) (*bunA
 		return nil, err
 	}
 
+	runtime.SetFinalizer(b, func(a *bunAdapter) {
+		if err := a.db.Close(); err != nil {
+			panic(err)
+		}
+	})
+
 	return b, nil
 }