A control wire which is secured at one end thereof to a bendable portion of the insert part of an endoscope is wound on a pulley which is rotatably provided in a control part, and a manual control device is provided outside the control part so as to be rotatable about a position which is offset from the axis of rotation of the pulley by a distance a. The rotational motion of the manual control device is transmitted to the pulley by a rotational motion transmitting device at a position which satisfies the conditions of c>a and c>b, wherein b is the distance from the transmitting device to the axis of rotation of the pulley and c is the distance from the transmitting device to the axis of rotation of the manual control device.