A liquid surface height inside a tank is allowed to be confirmed while blow-back of a liquid is reduced. A strainer body having a substantially bottomed tubular shape has a substantially D shape when viewed in a longitudinal direction. A bottom surface of the strainer body has a shape in which a part of a conical shape is cut away, and a top of the substantially conical shape overlaps with a notched portion notched to form the substantially D shape. The bottom surface protrudes toward an opening of the strainer body. A rod is provided adjacent to the notched portion of the strainer body, and a float is provided on a lower end of the rod.