PURPOSE: To arrange a door member and a heating chamber at a position where their easy operations can be carried out and to improve a degree of combination of freedom between an upper equipment and a high frequency heater device by a method wherein a controller for an upper equipment such as an electric heater or the like is removably attached to a part of an operating panel.

CONSTITUTION: An upper surface 11a of an outer shell 11 is provided with a second opening 11b at an adjoining part of a first opening 16b. A controller 20 for an electric heater 19 passes through a second opening 11b and is fitted while the front surface being adjacent to the first opening 16b. In this way, the operating part 16a for a main body of the device is arranged at a left half side while the upper surface 11a of the outer shell 11 and an upper end of the operating panel 16 are being substantially coincided to each other. The controller 20 for the electric heater 19 is removably arranged at a right half side. Accordingly, the operating parts of the main body of the device and the electric beater 19 are made integral to each other to cause the spacing to be made compact. The heating chamber 12 and the door 13 can be arranged at a higher position where their operations can be easily performed, resulting in that a convenience in use of the device can be improved. If another upper equipment is purchased, the equipment can be easily assembled in it and this a degree of freedom of selection of product of a consumer can be improved.