Gear-shaped resin sheets Sa are laminated such that tooth portions 2b are aligned in an axial direction, thereby preparing a spur gear-shaped net-shape body 4. Tooth portions of the resin gear formed in a lower die 12 are pressed in a helical tooth-shaped molding space to deform the tooth portions 4a of the net-shape body 4 into a helical tooth tilted relative to the axial direction, and the direction of reinforcement fibers at the tooth portions 2b of the molded resin gear 1 is tilted relative to the axial direction.