PURPOSE: To enable variable cooking to be performed and facilitate a correction of irregularity by a method wherein a level of menu switch output signal is made variable, a control information is divided, and a heating temperature and a heating time are controlled by a computer as a function of a set level.

CONSTITUTION: Signal level variable dividing resistors 13AW13C are arranged at an output signal line of a menu switch, an output level of the menu switch is adjusted and fed to a microcomputer 8. The computer 8 discriminates an operating menus switch under a combination of switch output signals of 3 bits and further discriminates a cooking condition. Control information for use in controlling a heating time and a heating temperature is divided into some segments in response to a level step which can be set by divisional resistors 13AW13C, and stored in a memory ROM and then controlled in response to the heating time and the temperature as a function of the discriminated menu switch output signal. In this way, it is made possible to facilitate a correction of dispersion in a temperature sensor.