PURPOSE: To enhance the strength of fittings by installing a male type metal fitting having a flanged part in the central part and a female type metal fitting which is fixed with the first half part of the male type metal fitting and the flanged part by means of a bolt whose fork part is inserted into an insertion hole.

CONSTITUTION: There are provided a rear end enlargement part to be buried and molded on the tip of a same cross section-flanged part of a CFRP member 1 and a same cross section flange to a transverse section of the member 1 in the central part and, what is more, there are provided a plurality of bolt holes on the first half part, thereby forming a steel-made fitting 3 whose side is rectangular and cross-shaped. There is also formed a steel member 2 having an outside cross section equivalent to the fitting 3 and moreover, having a fork unit which is fork end-shaped. The embedding side of the fitting 3 is buried and molded in the member 1 while the first half part of the fitting 3 is clamped with the fork unit of the steel member 2 and fastened with a bolt and a nut by way of the bolt hole 4.