Understanding of interaction reactions between materials and tissue in the body is necessary for the success of implant devices. Impedance and polarisation properties at the interface on 316L stainless steel and pure Ti under cell culture environment of fibroblast L929 or with collagen coating were examined. Limitation of mass diffusion at the interface by cell bodies and extracellular matrix is probably a corrosion factor of the presence of cells, which causes the decrease of protectiveness of passive film on 316L steel. Surface composition of 316L steel and Ti formed with L929 was compared with that formed in human body. Similar elements were detected on the surface formed in both the environments. The precipitated sulphur on the surface formed under cell culture and in the human body appears to be originated from proteins that might be produced by cells.