In endoscopic laryngo-pharyngeal surgery (ELPS), surgeons use an arc-shaped forceps and tools to remove the affected portion by observing it with a flexible endoscope. Because the direction of the endoscopic view and that of the forceps handle are different, surgeons are required of high manipulation skills. To overcome this problem, we have proposed a 3-DOF mechanical motion converter, which converts the backward and forward input motion to the rotating motion about the arc center of the forceps. The experiment with the first prototype showed the enhancement of the controllability. However, the device is too large for installing in the operating workspace. In this paper, we developed a new motion converter taking account of the installable workspace in the operation.