The present invention relates to a water level sensor for a water supply device of an automatic feeder, comprising: a sensor rod (300) to detect a level of water； a coupling means (200) wherein the sensor rod (300) is coupled； and a metal wire (400) connected to the coupling means (200) to transfer a signal to a control panel. According to the present invention, due to the water level sensor, the water in a feeding plate is always maintained at a constant level, and the water supplied from a nipple is properly supplied even when a pig randomly operates the nipple； thereby preventing any waste of water or feed and reduce together the necessary workforce with reduction of wastewater. When the water in the feeding plate is set at a proper level of water, the water is mixed with the feed by a proper ratio when the feed is added to the feeding plate； thereby increasing an amount of intake of feed by the pig and make the pig eat completely the feed to maintain a clean feeding plate for improved hygiene and health of the pig and enhance the health of the sows while nursing the piglets. More specifically, as the water supply is stopped when the water in the feeding plate reaches a constant level of water even if the nipple is out of order, the waste of water such as overflow, etc., are prevented. As the water level sensor is able to be moved when the pig pulls a lower part of the water level sensor, wet feed is prevented from sticking on the water level sensor which allows the water level sensor to operate correctly, and the pig is able to easily eat the feed on a lower part of the water level sensor. The metallic sensor rod of the water level sensor is installed in the water supply device of the automatic feeder to allow rotation with respect to a coupling device； thereby making installation more convenient and eliminating a cause of failure after installation of the water level sensor.본 발명은 자동 사료급이기의 물공급장치용 수위감지센서에 관한 것으로, 수위를 감지하는 센서봉(300)과, 상기 센서봉(300)이 결합되는 결합수단(200)과,
