To prevent a wrench suited for gripping reinforcement from being damaged on contact with reinforcement or causing damage to the reinforcement.

In a wrench 12, a longitudinally extending oblong hole 17 is provided in the sliding area of the movable jaw 16 of a handle 14, an engaging tooth shape 18 is provided on the upper inside surface of the oblong hole 17, and the movable jaw 16 is formed of an operating part 21 extending along the upper surface of the handle, an engaging part 22 located inside the oblong hole, a gripping part 23 extending along the lower surface of the handle, and each side plate part for fixing them integrally with one another. When the fixed jaw 15 side of the upper surface of the gripping part 23 is pressed against the lower surface of the handle by the elastic force of a spring 27, the lower surface of the operating part 21 is inclined with respect to the upper surface of the handle in such a way as to open the fixed jaw side, and the engaging tooth shape 28 formed in the engaging part 22 meshes with the engaging tooth shape 18 on the oblong hole to position the movable jaw 16; when the lower surface of the operating part 21 is pressed against the upper surface of the handle against the elastic force of the spring, the engaging tooth shape 28 of the engaging part 22 is disengaged from the engaging tooth shape 18 on the oblong hole, so that the movable jaw 16 can slide.