PROBLEM TO BE SOLVED: To provide a steam pasteurizer capable of supplying water into a chamber in a short time.SOLUTION: The steam pasteurizer 1 is equipped with a chamber 10 housing an object to be pasteurized and a heater 12 for heating the water supplied into the chamber 10 and the object to be pasteurized is pasteurized by the steam generated by heating the water in the same by the heater 12. The steam pasteurizer is also equipped with a lower limit water level sensor 15 for detecting the water level in the chamber 10 and a control part for controlling the operation of the steam pasteurizer 1. When the supply of water to the chamber 10 is started, the control part cools the heater 12 in a case that the water level in the chamber 10 is detected by the lower limit water level sensor 15 and the water level in the chamber 10 is determined to be below a lower limit water level before the supply of water.
