PURPOSE: To surely execute shrinkage fit in the first stage by providing a supporting tool in which a bar-like member is fitted with an upper and a lower strings in tensile condition at its respective ends and supported in conformity to a through hole in its axis line, and a journaling mechanism to journal the supporting tool to be movable in the direction of axis of the through hole.

CONSTITUTION: One end part of an upper string 4 is fitted to the upper end center part of a bar-like member 3, and one end part of a lower string 5 is fitted to the lower end center part of the member 3. The other member 1 is heated to spread the bore of a through hole 2, and the bar-like member 3 supported over it is at the normal temperature or cooled if necessary. When a supporting tool 6 is moved with a journaling mechanism 7 in the arrow mark A direction, by moving the supporting tool 6 without contact between the member 3 and the inner face of the through hole 2, the member 3 can be inserted into the through hole without fail, and by holding this condition penetrating shrinkage fit can be performed by expansion of the member 3 due to heat transfer from the member 1. After completion of shrinkage fit, the strings 4, 5 are removed from the member 3, and the supporting tool 6 and the journaling mechanism 7 are withdrawn.