To improve usability for a user and save time, electricity and water resources required for sterilizing work by automatically executing the sterilizing work of bacteria proliferated in a steam generation route and a tank.
This steam generator is provided with a sterilizing mode of filling a heat exchange tank 3 with hot water till a full water level and heating and circulating the high temperature water by a sheath heater 5 and a circulating pump 7. After finishing the sterilizing work, a sterilizing mode completion flag is set in a nonvolatile memory and at the same time a drain valve 8 is opened to discharge the high temperature water in the heat exchange tank 3. After being set, the sterilizing mode completion flag is cleared a predetermined time later. Once the sterilizing work is executed, the sterilizing work is omitted within the predetermined time when the sterilizing mode completion flag is set.
TSUJIMARU YUJI
IWASHITA HIROYUKI
