This invention relates to an artificial knee joint which can replace a natural knee joint and in which plural flexions are formed at a bearing member, and more specifically to an artificial knee joint which comprises: a femur joint member that is joined at an end portion of a femur near a tibia and a tibia joint member that is joined at an end of a tibia near a femur. Seen from a plan view of the bearing member between the femur and tibia joint members, the artificial knee joint member is designed to copy an actual knee movement by having the curvature of a groove in the front portion that is different from the curvature of a groove in the rear portion. In addition, seen in the lateral view, the bearing is designed to have the curvatures of the front and rear portions different from each other. Therefore, the front portion is higher than and has a shorter curvature than the rear portion in case the front portion should be displaced, and the rear portion is lower than and has a longer curvature than the front portion so that more natural flexion may occur in the rear portion. For this purpose, an artificial knee joint is provided in which a flexion is formed at the bearing member and includes a femur joint member which is joined to an end portion of a tibia near a femur a tibia joint member which is joined to an end portion of a femur near a tibia and a bearing member between the femur joint member and the tibia joint member, wherein the bearing member includes a groove where a planar front flexion and a planar rear flexion at an upper plane, in order to provide an artificial knee joint movement similar to a real knee movement.
