In a microwave oven, a driving motor is fitted inside a fitting member that is fixed to a cabinet. The upper part of the output spindle of the driving motor is disposed through the fitting member so as to protrude outward, and is fitted into the lower part of a linking member. The lower part of the rotary shaft of a turntable is fitted into the upper part of the linking member. The linking member is covered by a cover, and the lower part of the cover is fitted to the fitting member. On the upper part of and outside the cover, a coil spring for preventing leakage of radio waves is fitted so as to surround the rotary shaft. The coil spring is kept in close contact with the rim of a through hole formed in the bottom surface of a heating chamber. An overhang for drainage is formed in the linking member to prevent fluid from coming into contact with the output spindle.