A microwave oven or multifunctional oven with microwave heating function. The oven includes a cavity with an open front side and a front frame enclosing at least partially a front portion of the cavity. The cavity and the front frame include metal sheet. The front frame is connected to the cavity by fixing elements. A gap is formed between the cavity and the front frame. The gap encloses at least partially the front portion of the cavity and the front frame encloses the gap. The oven includes a door covering the open front side and the gap in a closed state of the door. The gap is at least partially filled by a gasket at least part of which includes one or more materials having low heat conductivity, so that the front frame is thermally decoupled from the cavity by the part of the gasket or the gap.