To provide a bolt for visually checking the axial force which can easily and visually check the preset tightening axial force at a space of the bolt or at the position of a head part by anybody even when any special measuring instrument is not carried in an assembly work or an outdoor tightening work.

A hollow columnar metal (3) with a metal (2) softer than that of a bolt head part (1) and a tapered part (4) under head assembled therein is assembled between the bolt head part (1) and a work (8A) to be tightened. A tapered part (4) in which the tapered angle of the biting force of the metal (2) softer than that of the bolt head part (1) and the tapered part (4) under head set therein according to the preset tightening axial force is provided. When the axial force is generated during the tightening condition, the hollow columnar metal (3) with the metal (2) softer than that of the bolt head part (1) and the tapered part (4) under head assembled therewith is bitten in the tapered part (4) under head of the bolt, and a space (S) becomes zero by the preset tightening axial force.