Abstract: A device and a method for controlling the rotation of the turntable of a microwave oven to return to the same position as when the present cooking cycle began. The device includes: an optical turntable rotation sensor unit, which is installed so as to emit an optical signal into a transmission hole, formed in the shaft of the turntable, during cooking and which is to recognize the rotation of the turntable by intermittently receiving the optical signal that passes through the transmission hole; and a microcomputer for controlling the rotation of the turntable after cooking has ended, if necessary, on the basis of the data from the turntable rotation sense unit. The rotation sense unit includes a photodiode and a phototransister. The transmission hole formed in the turntable shaft enables the optical signal emitted from the photodiode to pass through it and reach the phototransister.