A Three dimentional transparent physical model of a human head with real shape was constructed to visualize and measure relative motion between skull and brain in order to clarify the mechannism of acute subdural hematoma. The model consists of a transparant skul, brain made of syllicone gel, cerebrospinal fluid to reconstruct relative motion between brain and skull and meninges which constraints the motion. The shape was based on real-shaped three dimentional CAD data constructed from CT/MRI images of a specific individual. The results of experiments in the cases of impactor collision to the occipital skull showed that shape of impact force pulse applied to the head was not affected on maximum bridging vein strains because of relative motion between skull and brain due to existance of cerebro spinal fluid.