Abstract: A microwave oven comprises a heating element which produces heat by absorption of microwave radiation and on which is placed a material to be cooked with the interposition of a material support therebetween. If required, the heating element is disposed on a heat insulating body. A shield cover is arranged on the support for enclosing the material to be cooked placed on the support and for limiting the amount of microwave radiation which is allowed to be incident on the material from the exterior thereof. The material to be cooked is internally heated upon irradiation with the radiation and at the same time the heating element produces heat which is applied to the surface of the material through the material support. When the material support comprises a metal plate, an electric insulating body which prevents a spark discharge is arranged between the shield cover and the metal plate.