To provide a water level adjustment device for rice paddy capable of setting with a simple operation, a water level of a rice paddy and preventing a position of a water level which was set from displacing unexpectedly.SOLUTION: A water level adjustment device for adjusting a water level of a rice paddy to an optional height position comprises: a cylindrical tube-shaped movable tube whose one end and the other end are open surfaces, and into which service water on a rice paddy flows； a support medium having an opening into which the movable tube is inserted slidably along a center axis direction； and engagement means formed on the movable tube and the support medium, and engaging the movable tube to the support medium at an optional position along the center axis direction.SELECTED DRAWING: Figure 2【課題】水田の水位を簡易な操作で設定でき、しかも設定した水位の位置が予期せず変位することを防止できる水田用水位調節装置を提供する。【解決手段】水田の水位を任意の高さ位置に調節する水田用水位調節装置であって、一端および他端が開放面を成し、内部を水田の用水が流出する円筒管状の可動管と、該可動管が中心軸方向に沿って摺動自在に挿通される開口を備えた支持体と、前記可動管および前記支持体に形成され、前記可動管を中心軸方向に沿って前記支持体に対して任意の位置に係止させる係止手段と、を備えたことを特徴とする。【選択図】図２
