To eliminate the need for a welder by using no welding, to quicken the joining of a reinforcement by nonuse of grout mortar and to facilitate the joining of the reinforcement and improve quality.

A sheet 3 formed of fibers is arranged so as to wrap the reinforcements 1 and 2 over the joining sections of a plurality of joined reinforcements 1 and 2 extending over each joining section for the reinforcements. The sheet 3 is impregnated with an uncured resin 4 and the sheet 3 is stuck close to the reinforcements 1 and 2.