Recently, it is reported that risk of rupture of aneurysms is further less than risk of surgical complications. Therefore, to avoid unnecessary surgical operations, prediction of rupture of aneurysms is necessary. Because wall shear stress is known to play an important role for a vascular disease, the authors have investigated the relationship between wall shear stress and cerebral aneurysms. In this paper, numerical fluid-structure interaction analyses are performed to investigate influences of wall deformation on hemodynamic factors. The results show several patterns of arterial wall deformations and their influences on blood flow behavior and hemodynamic factors.