The impact-driven tool of the present invention includes a cylinder and a piston slidably inserted into the cylinder and having a large-diameter portion. The cylinder includes: a chamber on one end side that is a space defined by an outer surface of the piston located more on the one end side in the axial direction than the large-diameter portion of the piston and an inner surface of the cylinder; a chamber on the other end side that is a space defined by an outer surface of the piston located more on the other end side in the axial direction than the large-diameter portion of the piston and an inner surface of the cylinder; a communication path that allows the chamber on one end side and the chamber on the other end side to communicate with each other; and a valve chamber that is continuous with one end side in the axial direction of the communication path, and a valve body for piston lifting control that is incorporated so as to be movable up and down is provided in the valve chamber. The communication path is opened and closed by the valve body, thereby enabling the reduction in diameter and length of the valve body, so that the conduits of the hydraulic oil are maintained while the weight of the valve body is reduced.