To provide a clamp capable of securing strong and appropriate tightening force with small force and performing release through one action.

The base end part of a self-locking pawl member 6 is pivotally provided on a pin shaft 5 disposed on the fixing plate of a base metal fitting 2 and a locking end 7 is elastically energized in a direction to be in pressure contact with the surface of the fixing plate 3 at all times. The base end part of a feed handle 18 is pivotally provided on the pin shaft 5, a handle end 12 is rocked and the handle end 12 is elastically energized in the direction to be housed. Also, one end of a ratchet member 13 is pivotally provided on the middle part of the feed handle 10, a feed end 18 is elastically energized in the direction to be in pressure contact with the surface of the fixing plate 3 of the base metal fitting 2 at all times to constitute this clamp 1. A rack-like belt 30 for which a rack belt part 33 composed by arranging many locking gear teeth 32 side by side is formed is inserted and locked under the self-locking pawl member 6 and the feed handle 10 along the front surface of the fixing plate 3 of the base metal fitting 2 of the clamp 1 and tightening is adjusted by the rocking operation of the handle end 12.