To aim at facilitating supply of inexpensive a tightening component and a tightening tool which can do visual confirmation briefly that tightening of the tightening component is executed certainly, eliminate the tightening work confirmation after construction and control a tightening torque as well, in the tightening work of the tightening component.

A slot for scrape 3 is formed on a paint adherent face 2 of nut B, and the nut B is tightened with prescribed torque or more by a torque wrench, the paint adherent face 2 is scrubbed by a scrubbing edge 1 provided to torque wrench A. The tightening tool is characterized to composed such that scrubbing-off of the paint can be done easily by catching the scrubbing edge 1 on the slot for the scrape 3.