To connect PCa members with tensioning force (prestress) of a PC steel bar tightly while facilitating introduction of the tensioning force using a torque wrench, and reliably notify that the tensioning force has been transmitted over the whole PC steel bar even if the tensioning of the PC steel bar is introduced by torque control.

A PC steel bar 9 is disposed between precast concrete members 1, 2 to be connected. Nuts 13, 13a are screwed into male screws 9a formed at both ends of the PC steel bar 9. The method of connecting the concrete members 1, 2 by fastening one nut 13 fills an adhesive 40 to the periphery of the PC steel bar 9 and curing it to bond the PC steel bar 9 to the members 1, 2, rotates the nut 13 to be fastened to cut the adhesive 40, and crimp-connects the precast concrete members 1,2.