A thermal processing apparatus comprising a processing vessel containing, in addition to a plurality of objects subject to heat treatment, an acoustic wave device for temperature measurement. A holding unit holds the plurality of objects to be processed and an object for temperature measurement utilizing an acoustic wave device. A heating unit heats the objects to be processed and the object for temperature measurement. A first conductive member functions as an antenna for transmitting an electromagnetic wave toward the acoustic wave device in the processing vessel; a second conductive member functions as a receiver antenna for receiving an electromagnetic wave dependent on a temperature of the acoustic wave device which is emitted from the acoustic wave device. A temperature analysis part obtains a temperature of the object based on the electromagnetic wave received by the receiver antenna, and a temperature control part controls the heating unit. The first and second conductive members are each part of the thermal processing parts in the processing vessel.