PURPOSE: To enable transferring wafers of the same kind by means of the same wafer transfer unit and to obtain semiconductor elements of good quality by providing each boat loading station (27) with a wafer transfer unit.

CONSTITUTION: A wafer 32 on each carrier 31 is aligned its orientation flat by an orientation flat matching unit, and after that, the wafers 32 are carried to a wafer transfer position, are pushed up by a pushup unit and are chucked by the wafer chucks 36 and 37 of a wafer transfer unit 34. In this state, after a wafer boat 33 is ridden on a paddle 42 and is placed and fixed on a boat tray 42, the wafer chucks 36 and 37 are opened to transfer the wafers 32 on the wafer boat 33. After the transfer ends, the paddle 41 is extended to the direction of a multi-stage furnace 20 to insert the wafer boat 33 in a tube 24, the wafer boat 33 is put in the tube 24, the paddle 41 is returned to its former position, the tube 24 is covered with a quartz autocap 44 and a heat treatment for the wafers 32 is executed.