A wall-mounted type microwave oven includes an outer cabinet defining an outer appearance thereof, an inner cabinet disposed in the outer cabinet to define a flow path therebetween, a sensor disposed in the flow path to check conditions of air flowing in the flow path, and a terminal unit connected to the sensor to transmit electric power and control signals to the sensor. The flow path includes a fitting hole to hold the sensor and the terminal unit. A sensor holder receives the sensor and the terminal unit, and is detachably fitted in the fitting hole. Only an operation of separating the sensor holder from a guide duct is performed in the guide duct, and an operation of pulling the sensor and the terminal unit out of the sensor holder and detaching the sensor from the terminal unit is performed outside the guide duct.