Abstract: A cerebral aneurysm clip used for clamping an intercerebral blood vessel during a surgical operation. The clip has a pair of opposite clamping blades or arms for clamping a blood vessel, semi-circular engagement portions integrally connected to the proximal ends of the clamping arms, and a resilient wire portion integrally connecting the two engagement portions for exerting a resilient clamping force to the clamping arms via the engagement portions. The clamping arms are opened and closed by manipulating forceps which has at its tip engagement protrusions engaging the engagement portions from the inside. In order to prevent a blood vessel from passing excessively beyond the region between the opposite clamping arms, a U-shaped wire element is attached to the clip. The wire element has a transverse section passed through and across the proximal ends of the clamping arms for preventing ingress of the blood vessel into the space between the engagement portions.