An endoscopic system includes a surgical instrument position control apparatus. The surgical instrument position control apparatus estimates motion of an endoscope main body with respect to a target site, based on an image picked up in conjunction with movement of an endoscope. The surgical instrument position control apparatus then estimates motion of a surgical instrument moving integrally with the endoscope main body based on the motion of the endoscope main body. To determine the moving amount of the surgical instrument, the surgical instrument position control apparatus calculates the amounts of operations, such as bending, rotation, and forward and backward movements, of each joint of a surgical arm section 21c which amounts are required to move the surgical instrument from a position taken by the surgical instrument after movement of the endoscope to a surgical procedure position. The surgical instrument position control apparatus thus bends each joint to move the surgical section to the original surgical procedure position so as to hold the position of the surgical instrument every time the endoscope is moved.
