The present invention provides an automatic water supply interruption device for farmland supply which may reduce the labor and time for maintenance. The automatic water supply interruption device (3) of the present invention comprises: a water gauge unit (4) which may be detachably disposed in the farmland (1) for checking if the water level in the farmland (1) is raised to the specified water level； and, a valve unit (5) of a water supply pipe (2) disposed for farmland (1) supply. In which, the valve unit (5) comprises: a valve (11) capable of opening and closing the water supply pipe (2) and a closed position moving means (12) for moving the valve (11) from the opened position for opening the water supply pipe (2) toward the closed position for closing the water supply pipe. Between the water gauge unit (4) and the valve unit (5), there is provided with: a transmission body (13) for transmitting the specified water level checking result generated by the water gauge unit (4), and an action instruction body (14) for instructing the closed position moving means (12) based on the checking result transmitted from the transmission body (13). In which, the water gauge unit (4) and the valve unit (5) are detachably combined between the action instruction body (14) and the valve unit (5).[課題] 提供可以將維修的勞力和時間減輕的朝田地供給的供水自動遮斷裝置。[技術內容] 供水自動遮斷裝置(3)，是具備：可取出地被設置在田地(1)且檢出該田地(1)內的水位上昇至規定水位用的水位計單元(4)、及被設於朝田地(1)供給的供水路(2)的閥體單元(5)。閥體單元(5)，是具備：將供水路(2)開閉的閥體(11)、及將該閥體(11)從將供水路(2)開放的開位置朝閉鎖的閉位置移動的閉位置移動手段(12)。在水位計單元(4)及閥體單元(5)之間，是設有：將由水位計單元(4)所產生的規定水位的檢出傳達的傳達體(13)、及依據從該傳達體(13)被傳達的檢出使閉位置移動手段(12)作動的作動指示體(14)。在此，水位計單元(4)及閥體單元(5)，是可分離地連結在作動指示體(14)及閥體單元(5)之間。
