Mandrel for manufacturing fiber reinforced resin vessel

A mandrel for manufacturing a fiber reinforced resin vessel by a filament winding process, comprising:

• a tubular part;
• and
• a pair of end parts joined to respective axial ends of the tubular part;
• wherein the tubular part and the end parts are each made of a molded product of a material including pulp and a starch-based binder, and
• the tubular part includes a cylindrical outer peripheral wall having a central axial line, a planar partition wall extending radially inward and orthogonally to the central axial line from a first end of the outer peripheral wall, and a plurality of bulging parts bulging from the partition wall toward a second end of the outer peripheral wall, each bulging part being connected to an inner circumferential surface of the outer peripheral wall.