diff --git a/cmd/migrate_command_test.go b/cmd/migrate_command_test.go
index 45682cf9..a7c82dd4 100644
--- a/cmd/migrate_command_test.go
+++ b/cmd/migrate_command_test.go
@@ -111,7 +111,7 @@ provider "azurerm" {
 			ErrorWriter: os.Stderr,
 		},
 	}
-	p, err := terraform.Plan()
+	p, err := terraform.Plan(nil)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -182,7 +182,7 @@ provider "azurerm" {
 	}
 
 	// check no plan-diff
-	plan, err := terraform.Plan()
+	plan, err := terraform.Plan(nil)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/cmd/plan_command.go b/cmd/plan_command.go
index 0ca685f5..06897269 100644
--- a/cmd/plan_command.go
+++ b/cmd/plan_command.go
@@ -80,7 +80,7 @@ func (c *PlanCommand) Synopsis() string {
 func (c *PlanCommand) Plan(terraform *tf.Terraform, isPlanOnly bool) []types.AzureResource {
 	// get azapi resource from state
 	log.Printf("[INFO] running terraform plan...")
-	p, err := terraform.Plan(c.varFile)
+	p, err := terraform.Plan(&c.varFile)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/tf/terraform.go b/tf/terraform.go
index 6850cf94..290701d2 100644
--- a/tf/terraform.go
+++ b/tf/terraform.go
@@ -69,10 +69,10 @@ func (t *Terraform) Show() (*tfjson.State, error) {
 	return t.exec.Show(context.TODO())
 }
 
-func (t *Terraform) Plan(varFile string) (*tfjson.Plan, error) {
+func (t *Terraform) Plan(varFile *string) (*tfjson.Plan, error) {
 	planOptions := []tfexec.PlanOption{tfexec.Out(planfile)}
-	if varFile != "" {
-		planOptions = append(planOptions, tfexec.VarFile(varFile))
+	if varFile != nil && *varFile != "" {
+		planOptions = append(planOptions, tfexec.VarFile(*varFile))
 	}
 	_, err := t.exec.Plan(context.TODO(), planOptions...)
 	if err != nil {