A
transfer mechanism 21 of a vertical heat
treatment system 1 includes a base capable of vertical movement and turning movement, and plural substrate support devices, disposed on the base so as to be movable anteroposterior, that hold wafers W. Provided on the base 25 is a first sensor 45 that emits a
light beam directed toward a direction in which the substrate support device 20 moves anteroposterior, and detects the target member upon
receipt of a reflected light of the
light beam. Provided on two tip end portions of the substrate support device 20 is a second sensor 40 that detects the target member upon interruption of a
light beam traveling between the tip end portions by the target member. When a target member 44 provided at its specific positions with projections 49 and 50 is placed at a position in a
wafer boat 8, the base 25 moves vertically and turns, and the substrate support device 20 moves anteroposterior. The position of the target member, or the transfer target position of the
wafer, is automatically detected based on the detection signals of the first sensor 45 and the second sensor obtained at the time and
encoder values of drive systems relating to the movement of the base 25 and the substrate support member 20.