To provide a clamping tool capable of clamping and screw-moving a fastening member in a non-turnable state due to the crush of a fit-in groove.

This clamping tool comprises a grip operating part 1 formed by pivoting a pair of grip half bodies 1A, 1B to each other in an openable/closable manner, and a clamping part 2 provided at the tip part of the grip operating part 1 and put in closing motion by the grip operation of the grip operating part 1 through a toggle mechanism T to clamp a clamped object 3. A clamping lock mechanism R is provided for locking the clamping state of the clamping part 2 when the clamped object 3 is clamped by the clamping part 2 by the grip operation of the grip operating part 1, and engaging recessed parts 4, 5 ruggedly engaged with the peripheral surface of a head 3a of the fastening member 3 such as a machine screw or a screw which is the clamped object 3, are formed at the facing clamping surfaces 2A, 2B of the clamping part 2.