PURPOSE: To provide the joint structure of an FRP(fiber reinforced plastic) shaft and a joint and the joining method of them which is high in concentricity and straightness and retains high adhesive strength.

CONSTITUTION: This joint structure is concerned with a joint structure and a joining method wherein a joint section which is tight in engagement, and is composed of a plurality of projected ribs 18 extended in the axial direction, is formed in the outer circumferential surface of the joint section 17 of a flange joint 12, and both the outer circumferential surface of the joint section 17 and the end section inner circumferential surface of a shaft 11 made of FRP(fiber reinforced plastic) are coated with adhesives, and the joint 12 is then inserted into the end section of the shaft 11 so as to be bonded and fixed therein.