In-plane temperature of each substrate is uniformly controlled at the time of heating substrates placed on a plurality of susceptors, respectively. A heat treatment apparatus is provided with susceptors, i.e., conductive members for placing wafers thereon, having an induction heating body electrically divided into a center portion thereof and a peripheral portion thereof; a quartz boat supporting the susceptors arranged in a row; an induction coil, which is arranged inside a processing chamber to surround the circumference of each of the susceptors and configured such that the temperature of the induction coil can be freely adjusted; and a control unit which performs temperature control by changing the ratio between heat value at the center portion of the induction heating body and that at the peripheral portion, by controlling two high frequency currents of different frequencies to be applied to the induction coil from a high frequency current circuit.