The present invention relates to an internal cavity combination body of microwave oven. Said combination body includes front plate, rear plate and top plate. Said front plate has inlet of roasting cavity and is formed into front panel. The rear plate is formed into the back face of roasting cavity and is connected with bottom plate. Its top plate is formed into upper top surface of roasting cavity, and its two sides ends are connected with bottom plate. Its front end and rear end are respectively connected with front plate and rear plate. It also includes bottom plate which is formed into two side walls and bottom surface of roasting cavity. |