PURPOSE: To prevent dust from occurring and to improve cleanness by providing a boat fixation releasing mechanism formed of springs that provide a restoring force to a large cylinder and by equipping a master cylinder that externally provides a releasing force to the large cylinder.

CONSTITUTION: A wafer push-up means 20 transports a wafer 18 held in a wafer holding groove 34 in the form of a comb at the lower side of a cassette 19 or a boat 22 to a wafer holding groove in the form of a comb at an upper side at the upward movement, and returns it to a wafer holding groove 34 in the form of a comb of the cassette 19 or a boat 22. A wafer transfer device having a cassette feed table 17 and a boat feed table 21 is equipped with a clamp plate 3 that fixed the boat 22 from both sides by the force of a spring, a small cylinder 52 that releases the boat fixed by both clamp plate 3 against the spring force, a large cylinder 51 that fixes and releases a boat 22, and a spring 56 that provides a restoring force to this large cylinder 51 on the boat feed table 21. The large cylinder 51 is equipped with a master cylinder 53 that externally provides a releasing force.