diff --git a/internal/provider/resource_vm.go b/internal/provider/resource_vm.go
index 4bdb36c..802b7d0 100644
--- a/internal/provider/resource_vm.go
+++ b/internal/provider/resource_vm.go
@@ -198,7 +198,7 @@ func resourceVm() *schema.Resource {
 						},
 						"iso_id": {
 							Type:        schema.TypeString,
-							Required:    true,
+							Optional:    true,
 							Description: "mount an ISO to a VM CD-ROM by specific it's id",
 						},
 						"id": {