This paper discusses the development and control of the master-slave system capable of grasping an object with unknown coefficient of static friction. Partial slip information is known to be essential for conducting stable grasping in teleoperating system. The developed partial slip sensor contains strain gages in several ridges placed on the curvature contact surface of the elastic body. By measuring strain velocity of each ridge with the strain gages, the vibration that occurs due to the partial slip can be detected. We developed the master-slave system with the slave robot uses the developed sensor to detect a partial slip and automatically controls the grasping force. When an operator intentionally decreases the grasping force applied to the master device in order to release an object, the suppressor suppresses grasping force that is automatically increased by the slave robot. Through the grasp manipulation experiment, the validity of the developed system was confirmed.