To provide a heating cooking appliance which can thaw mixed food of different kinds of foodstuffs (single food formed of separate kinds of foodstuffs such as an ingredient and rice of sushi) to be in a state of being suitable for each foodstuff.

The heating cooking appliance has a constitution wherein waveguides for guiding a high frequency supplied from a magnetron into a heating chamber are provided in the ceiling plate and a base plate respectively, and the mixed food in the heating chamber is heated with the high frequency from above and below. Herein a setting stage for the mixed food is provided in the heating chamber, and each foodstuff constituting the mixture food is disposed at a height position where one foodstuff and another can be brought into prescribed thawed states respectively in the same heating time.