Disclosed is a heat treatment apparatus including: a processing container configured to accommodate a substrate; a furnace body having a heater configured to heat the substrate accommodated in the processing container and provided around the processing container; a blower configured to supply a coolant to a space between the processing container and the furnace body; and a controller having a continuous operation mode in which the blower is continuously energized and an intermittent operation mode in which energization and de-energization of the blower are repeated, and configured to control driving of the blower based on an instruction voltage. The controller drives the blower in the intermittent operation mode when the instruction voltage is higher than 0 V and lower than a predetermined threshold voltage.