According to a water supply device of an automatic feed supply system of the present invention, a water supply pipe (80) having a nipple (90) installed on the lower end thereof is installed on the upper part or a lateral side of a water bowl (30) so as to supply water, wherein: the nipple (90) for a drinking purpose is formed at an end portion of the water supply pipe (80) and a water level detection sensor (43) is installed on the lateral side of the water bowl (30) such that when the water in the water bowl (30) does not exceed a certain level, the water level detection sensor (43) senses the water level and transmits a signal to a control unit so as to open an electronic valve which supplies water to the water supply pipe (80), such that when a pig moves, with its mouth, an opening and closing cork protruding from the lower part of the nipple (90), water comes out of the nipple (90) and if the water in the water bowl (30) reaches the certain level, the water level detection sensor senses the water level and transmits a signal to the control unit so as to close the electronic valve which supplies water to the water supply pipe (80), such that water does not come out of the nipple (90) even though the pig moves the opening and closing cork of the nipple (90), thereby preventing the wasting of water. Thus, the present invention provides the remarkable effects of moving the water level detection sensor if a pig pushes the lower part of the water level detection sensor so as to prevent wet feed from sticking thereto such that the water level detection sensor can be accurately operated, and allowing a pig to easily eat feed of the lower part of the water level detection sensor.Selon un dispositif dalimentation en eau dun système de fourniture de nourriture automatique de la présente invention, un tuyau dalimentation en eau (80) ayant une tétine (90) installée sur son extrémité inférieure est installé sur la partie supérieure ou un côté latéral dune cuve deau (30) de fa
