To improve the tensile strength and radial strength of a resin lock bolt by pultrusion molding a fiber-reinforced plastic layer in the circumference of a cylindrical object formed of a resin pipe or a woven or knitted fabric and integrating them.

A fibir-reinforced plastic(FRP) layer is provided in the circumference of an internal reinforcing layer 1 that is made of a resin pipe or a woven or knitted fabric that is formed into a cylinder. By integrating the internal reinforcing layer 1 and the FRP layer 2, radial bursting strength is improved while maintaining axial tensile strength. The internal reinforcing layer 1 is made of all kinds of resins, aramid fibers or glass fibers. The FRP layer 2 is made of a resin and reinforcing fibers. As the resin, an epoxy vinyl ester resin can be given from the point of view of corrosion resistance, and as reinforcing fibers, glass, carbon or aramid fibers can be sited. It is preferable that an external layer 3 containing a fibrous material is provided in the circumference of the FRP layer 2.