PURPOSE: To maintain the optimum temperature of the surface of metallic die by measuring the temperature of surface of metallic die according to a prescribed temperature measuring route using a temperature sensor, comparing the target temperature to actual temperature and adjusting the atomizing quantity of release agent in accordance with the difference of target temperature and actual temperature.

CONSTITUTION: The temperature of surface of die of a cavity part 11a of fixed die 10 and movable die 11 is successively measured along the route using a temperature sensor such as radiation thermometer fitted to the main body 12 of a press and the obtained data are stored in a CPU. The target temperature of surface of die is preliminarily inputted in the CPU. A release agent 14 is sent to the main body 12 of a spray, atomized by compressed air and applied on the surface of cavity part 11a becoming liquid particles from a spray nozzle 12a. The atomizing quantity of release agent 14 is adjusted in accordance with the difference of actual temperature and target temperature and the temperature is corrected to be the target temperature. Thus, generation of defects of products such as defective circulation of melted metal or defective casting surface are reduced.