To solve problems of neither being separated by rust nor adjusting the height.

This sluice valve casing is provided with a bottom casing body being formed by projecting an annular projection to an upper face circumferential edge, an intermediate casing body mounted on and fixed to the bottom casing body, an adjustment casing body mounted on the intermediate casing body, a top casing body integrally fixing the intermediate casing body with the adjustment casing body, a cover body being fitted to the top casing body and a split ring fixing the bottom casing body or the top casing body. The top casing body is characterized in having an inward flange for mounting the cover body and a projecting piece preventing rattling with the adjustment casing body, and forming the bottom end in such a state as having a clearance for inserting the split ring toward the intermediate casing body. The intermediate casing body and the adjustment casing body is preferably made of plastic. This constitution can facilitate the assembling and detachment.