An anvil receives less stress around a rectangular prism and has higher durability. An impact wrench includes a motor, a hammer rotatable by the motor, a body accommodating the motor and the hammer, and an anvil protruding frontward from the body and to be struck in a rotation direction by the hammer. The anvil includes a blade to be in contact with the hammer, a cylinder located frontward from the blade, a rectangular prism located frontward from the cylinder, at least one chamfered surface each at an edge of the rectangular prism, and a concave on a rear end of the at least one chamfered surface.