A new type of bilateral servo controller for a master-slave robot system (MSRS) is proposed through the stability analysis based on the Liapunov theory. This controller is easily implementable and assures the asymptotic stability in a sense that just after the human operator leaves hold of the joystick, the position of the tip of slave arm asymptotically approaches the position of the joystick of master arm and eventually coincides with it, even if each of master and slave arms has a different structure and complex nonlinear dynamics. It possesses some remarkable functions indispensable for advanced teleoperation systems and consists of three control modes, viz. manual operation mode, force feedback control mode, and hybrid control mode, each of which is selected to use according to the substance of tasks. The performance of teleoperation under each control mode is comparatively examined by referring to experimental results.