[PROBLEMS] To provide a paddy water level detection system capable of accurately detecting the water level of a paddy field without being affected by sedimentation of mud, intrusion of dredging, garbage and the like. A paddy field water level detection system, comprising a column body standing on a paddy field, and an ultrasonic pulse which is provided on the column body, emits an ultrasonic pulse toward the water surface of the paddy field, and is reflected by the water surface of the paddy field. An ultrasonic sensor unit that receives and obtains various information, a saucer unit that is provided at the lower end of the column body, and the upper end edge is located on the surface of the soil layer, and the saucer unit is installed in the paddy field. Based on the paddy water level detection device 10 provided with a fixed pile to be fixed to a place and a water level information transmission unit for transmitting various information acquired by the ultrasonic sensor unit, the water level information of the paddy field is calculated based on the received various information. And the information management server 30 which transmits to the information communication terminal 40 of the manager of a paddy field or an agricultural worker, and the saucer part of the paddy field water level detection apparatus 10 moves up and down according to the state of the soil formation layer. [Selection] Figure 1【課題】泥の沈殿や、蜘蛛、ごみ等の侵入に影響されることなく、水田の水位を正確に検知することができる水田水位検知システムを提供する。【解決手段】水田水位検知システムであって、水田に立設された支柱体と、支柱体に設けられ、水田の水面方向へ超音波パルスを発射し、水田の水面で反射した超音波パルスを受信し、各種情報を取得する超音波センサ部と、支柱体の下端部に設けられ、その上端縁が作土層表面に位置するように埋設された受皿部と、受皿部を水田内の設置場所へ固定する固定杭と、超音波センサ部により取得された各種情報を送信する水位情報送信部とを備えた水田水位検知装置１０と、受信した各種情報に基づいて、水田の水位情報を算出し、水田の管理者、若しくは農業作業者の情報通信端末４０へ送信する情報管理サーバ３０とを有し、水田水位検知装置１０の受皿部は、作土層の状態に応じて上下動する。【選択図】図１
