PURPOSE: To hardly generate the dislocation and looseness of a once positioned bolt or the like and enlarge an adjustable range.

CONSTITUTION: A bearing member 2 for bearing an axially slidable shaft 1 is formed of a double-pitch screw component. A doulbe-pitch screw 4 formed of a small pitch screw and a large pitch screw respectively of smaller pitch and larger pitch in the same advance direction at the-pitch of a specified ratio is formed in the threaded hole 3 of the bearing member 2. Two check bolts 6, 7 to be screwed with the doublepitch screw 4 are to be single pitch screw components. The inner side check bolt 6 is screwed with the threaded hole first and stopped in a specified position. In this state, the outer side check bolt 7 to be screwed with the threaded hole is turned and clamped into the whirl-stop state.