A fuel tank includes: a tank main body made of a resin material; and a cover member which is formed using threads made of a fiber-reinforced composite material containing a thermoplastic resin fusible to a surface of the tank main body. The cover member has a twill weave structure at least in its portion fused to the upper surface of the tank main body. The threads each have a core-sheath structure in which a fiber made of a polypropylene resin is coated with a polyethylene resin.