To increase a turn prevention function of a ratchet anvil in the opposite direction by forming a housing body by a sturdy structure deforming not easily to enable smooth turn in one direction of forward and reverse directions of a jig and manufacture the sturdy housing body inexpensively without requiring much time and labor and advanced technical skill.

A ratchet yoke 21 and the ratchet anvil 22 are assembled and stored in the housing body 20 formed like a box having an opening part 28 and a U-shaped cross section. Moreover, a jig fixing part 37 protrudes to the outside from a lid body 30 covering the opening part 28 to press and energize the ratchet anvil 22 in the direction of the inside of the housing body 20 by an elastic body 40.