An insertion apparatus includes an inner guide sheaths 40, a fixing lever 80, and a moving member fixing mechanism 100 that fixes movement of the inner guide sheaths 40, and the moving member fixing mechanism 100 includes a guide member 117, a crank member 110 including a reciprocating portion 110a that is movable as the fixing lever 80 is operated, a pair of link members 115 that is openable and closable around a slider pin 130 as the crank member 110 is moved, and cam members 120 that are rotatable to a second rotation position where the cam members simultaneously press exposed sites 40r to wall surfaces 117w in a vertical direction R, and a first rotation position where the cam members are separated from the exposed sites 40r, by either one of opening and closing of the respective link members 115.
