A stent device for treating an aneurysm is disclosed. The stent device comprises an expandable balloon with a channel extending through said balloon from one side to another, and a supporting stent connected to said balloon. In an operative disposition, when the expandable balloon is expanded, the supporting stent is arranged at least partly within said channel of said expandable balloon. Further, the supporting stent has walls which are permeable to blood. The stent device may be introduced and removed by endoscopic procedures, with a relatively simple procedure. Thus, the stent device is highly useable for fast and temporary treatment of ruptured aneurysms.