PURPOSE: To improve the precision in measurement of the cumulative number of times of execution of cooling and the cumulative time of execution of cooking by setting the capacity of a smoothing capacitor to be large and by writing the number of times of execution of cooking and the time of execution of cooking in a nonvolatile memory at the time point when instantaneous power failure is recognized.

CONSTITUTION: The capacity of a smoothing capacitor incorporated in a power circuit 17 is set to be large, and at the time point when an instantaneous power failure is recognized by a microcomputer 11, the number of times of execution of cooking and the time for execution of cooking are written in a nonvolatile memory 12. Even when a power source is broken and this is judged as the instantaneous power failure, for instance, a voltage necessary for writing in the nonvolatile memory 12 is maintained for a prescribed time by the operation of the smoothing capacitor and the number of times of execution of cooking and the time of execution of cooking which are stored on the microcomputer 11 side are written in the nonvolatile memory 12. Thereby the precision in measurement of the cumulative number of times of execution of cooking and the cumulative time of execution of cooking is improved.