diff --git a/internal/context/context.go b/internal/context/context.go
index 5899b1e..757e07e 100644
--- a/internal/context/context.go
+++ b/internal/context/context.go
@@ -44,7 +44,7 @@ func Init() {
 }
 
 type NFContext interface {
-	AuthorizationCheck(token, serviceName string) error
+	AuthorizationCheck(token string, serviceName models.ServiceName) error
 }
 
 var _ NFContext = &NSSFContext{}
@@ -136,22 +136,22 @@ func GetSelf() *NSSFContext {
 	return &nssfContext
 }
 
-func (c *NSSFContext) GetTokenCtx(scope string, targetNF models.NfType) (
+func (c *NSSFContext) GetTokenCtx(serviceName models.ServiceName, targetNF models.NfType) (
 	context.Context, *models.ProblemDetails, error,
 ) {
 	if !c.OAuth2Required {
 		return context.TODO(), nil, nil
 	}
 	return oauth.GetTokenCtx(models.NfType_NSSF, targetNF,
-		c.NfId, c.NrfUri, scope)
+		c.NfId, c.NrfUri, string(serviceName))
 }
 
-func (c *NSSFContext) AuthorizationCheck(token, serviceName string) error {
+func (c *NSSFContext) AuthorizationCheck(token string, serviceName models.ServiceName) error {
 	if !c.OAuth2Required {
 		logger.UtilLog.Debugf("NSSFContext::AuthorizationCheck: OAuth2 not required\n")
 		return nil
 	}
 
 	logger.UtilLog.Debugf("NSSFContext::AuthorizationCheck: token[%s] serviceName[%s]\n", token, serviceName)
-	return oauth.VerifyOAuth(token, serviceName, c.NrfCertPem)
+	return oauth.VerifyOAuth(token, string(serviceName), c.NrfCertPem)
 }
diff --git a/internal/sbi/consumer/nf_management.go b/internal/sbi/consumer/nf_management.go
index 1274e46..f6d4bdf 100644
--- a/internal/sbi/consumer/nf_management.go
+++ b/internal/sbi/consumer/nf_management.go
@@ -93,7 +93,7 @@ func SendDeregisterNFInstance() (*models.ProblemDetails, error) {
 
 	var err error
 
-	ctx, pd, err := nssf_context.GetSelf().GetTokenCtx("nnrf-nfm", models.NfType_NRF)
+	ctx, pd, err := nssf_context.GetSelf().GetTokenCtx(models.ServiceName_NNRF_NFM, models.NfType_NRF)
 	if err != nil {
 		return pd, err
 	}
diff --git a/internal/sbi/nssaiavailability/routers.go b/internal/sbi/nssaiavailability/routers.go
index ee285f7..4cccca1 100644
--- a/internal/sbi/nssaiavailability/routers.go
+++ b/internal/sbi/nssaiavailability/routers.go
@@ -23,8 +23,6 @@ import (
 	logger_util "github.com/free5gc/util/logger"
 )
 
-const serviceName string = string(models.ServiceName_NNSSF_NSSAIAVAILABILITY)
-
 // Route is the information for every URI.
 type Route struct {
 	// Name is the name of this Route.
@@ -50,7 +48,7 @@ func NewRouter() *gin.Engine {
 func AddService(engine *gin.Engine) *gin.RouterGroup {
 	group := engine.Group(factory.NssfNssaiavailResUriPrefix)
 
-	routerAuthorizationCheck := util.NewRouterAuthorizationCheck(serviceName)
+	routerAuthorizationCheck := util.NewRouterAuthorizationCheck(models.ServiceName_NNSSF_NSSAIAVAILABILITY)
 	group.Use(func(c *gin.Context) {
 		routerAuthorizationCheck.Check(c, nssf_context.GetSelf())
 	})
diff --git a/internal/sbi/nsselection/routers.go b/internal/sbi/nsselection/routers.go
index c347505..f5f0b7c 100644
--- a/internal/sbi/nsselection/routers.go
+++ b/internal/sbi/nsselection/routers.go
@@ -23,8 +23,6 @@ import (
 	logger_util "github.com/free5gc/util/logger"
 )
 
-const serviceName string = string(models.ServiceName_NNSSF_NSSELECTION)
-
 // Route is the information for every URI.
 type Route struct {
 	// Name is the name of this Route.
@@ -50,7 +48,7 @@ func NewRouter() *gin.Engine {
 func AddService(engine *gin.Engine) *gin.RouterGroup {
 	group := engine.Group(factory.NssfNsselectResUriPrefix)
 
-	routerAuthorizationCheck := util.NewRouterAuthorizationCheck(serviceName)
+	routerAuthorizationCheck := util.NewRouterAuthorizationCheck(models.ServiceName_NNSSF_NSSELECTION)
 	group.Use(func(c *gin.Context) {
 		routerAuthorizationCheck.Check(c, nssf_context.GetSelf())
 	})
diff --git a/internal/util/router_auth_check.go b/internal/util/router_auth_check.go
index 1943d64..ede9ad3 100644
--- a/internal/util/router_auth_check.go
+++ b/internal/util/router_auth_check.go
@@ -7,13 +7,14 @@ import (
 
 	nssf_context "github.com/free5gc/nssf/internal/context"
 	"github.com/free5gc/nssf/internal/logger"
+	"github.com/free5gc/openapi/models"
 )
 
 type RouterAuthorizationCheck struct {
-	serviceName string
+	serviceName models.ServiceName
 }
 
-func NewRouterAuthorizationCheck(serviceName string) *RouterAuthorizationCheck {
+func NewRouterAuthorizationCheck(serviceName models.ServiceName) *RouterAuthorizationCheck {
 	return &RouterAuthorizationCheck{
 		serviceName: serviceName,
 	}
diff --git a/internal/util/router_auth_check_test.go b/internal/util/router_auth_check_test.go
index bf4ecf0..0d6ec07 100644
--- a/internal/util/router_auth_check_test.go
+++ b/internal/util/router_auth_check_test.go
@@ -7,6 +7,8 @@ import (
 
 	"github.com/gin-gonic/gin"
 	"github.com/pkg/errors"
+
+	"github.com/free5gc/openapi/models"
 )
 
 const (
@@ -20,7 +22,7 @@ func newMockNSSFContext() *mockNSSFContext {
 	return &mockNSSFContext{}
 }
 
-func (m *mockNSSFContext) AuthorizationCheck(token string, serviceName string) error {
+func (m *mockNSSFContext) AuthorizationCheck(token string, serviceName models.ServiceName) error {
 	if token == Valid {
 		return nil
 	}
@@ -81,7 +83,9 @@ func TestRouterAuthorizationCheck_Check(t *testing.T) {
 			}
 			c.Request.Header.Set("Authorization", tt.args.token)
 
-			rac := NewRouterAuthorizationCheck("testService")
+			var testService models.ServiceName = "testService"
+
+			rac := NewRouterAuthorizationCheck(testService)
 			rac.Check(c, newMockNSSFContext())
 			if w.Code != tt.want.statusCode {
 				t.Errorf("StatusCode should be %d, but got %d", tt.want.statusCode, w.Code)