Abstract: In the hydraulic tool, a main body section includes a cylinder and a piston. A head section is attached to the cylinder, includes a movable part. The piston is capable of rotating about the cylinder with the movable part. A control section is provided to the cylinder and includes oil paths and a switching valve. A piston valve reciprocally moves to control communication between a first and a second cylinder chambers. A concave is provided in a bottom face of the cylinder, escapes an end of the piston valve from a position at which the end of the piston valve contacts a bottom face, and shuts off the communication between the chambers. A projection is provided at a position different from the concave, makes the end of the piston valve contact the bottom face and allows the communication between the chambers.