Disclosed is a heat treatment apparatus including: a heating unit that heats an inside of a processing chamber that accommodates a plurality of workpieces; a temperature drop rate model storing unit that stores a temperature drop rate model; and a heat treatment performing unit that sets the temperature drop rate model stored in the temperature drop model storing unit and sets the inside of the processing chamber to the temperature and the time represented in the temperature drop rate model. The temperature drop rate model storing unit stores a plurality of temperature drop rate models, each of which has a different temperature drop rate. The processing chamber is divided into a plurality of zones, and the temperature drop rate mode is set for each of the zones. The heat treatment performing unit sets different temperature drop rate models in a plurality of zones to heat the plurality of workpieces.