To provide a method of making a position adjustment of a column base and position adjustments of respective members such as a column and a beam with small restrictions on use places using a compact member with a simple structure for steel-framed building, and a tool used therefor.

The position of the column base is adjusted by fitting a hole bored in the core of the column base in advance around a column base positioning bolt which can be fixed with mortar after an installation position is finely adjusted to the position of the column base using a concrete form coupling bolt fitted to a concrete form. For an adjustment of a column interval, namely, a position adjustment between the column and beam, joining plates are fitted to the column and beam respectively in adance, and a column interval adjusting tool is used which can adjust the mutual distance between the joining plates.