A microwave oven including a component compartment and a cooking compartment each including a discharging part to discharge air in the cooking compartment through the cooking compartment through portion; a supplying fan introducing the air to the component compartment through portion to cool the component compartment; a discharging fan introducing the air in the cooking compartment to the discharging part through the cooking compartment through portion; a fan motor between the supplying fan and the discharging fan to operate the supplying fan and the discharging fan; and an interfering part to interfere with the fan assembly when at least one of the supplying fan and the discharging fan is not in a predetermined position corresponding to the component compartment through portion and the discharging part.