The film-formation processing furnace 80 is provided with a wafer mounting/removal chamber 83 in a lower portion of the reaction vessel 81, and the wafer mounting/removal chamber 83 is provided with a wafer boat 86 which is capable of housing up to, for example, 100 of the semiconductor wafers W and which is mounted on a boat elevator mechanism 85 that is elevated by a means such as a ball screw 8