Rack housing manufacturing method and rack housing

A rack housing manufacturing method comprising:

• setting metal rings for coupling with or for insertion of different members in regions of a mold corresponding to coupling portions, the mold corresponding to a three-dimensional shape of a rack housing including a tubular portion that covers a rack shaft and the coupling portions which are continuous with both ends of the tubular portion to be coupled to the different members, and setting two heated prepregs in a region of the mold corresponding to the tubular portion, the prepregs being formed by stacking at least two layers of fiber-reinforced composite materials obtained by impregnating fiber sheets with a thermoplastic resin;
• clamping a die to form the two prepregs by press forming each into a shape having a semi-tubular body corresponding to half a circumference of the tubular portion and connecting portions in a flat plate shape extending outward from both ends of the semi-tubular body in a circumferential direction over an entire length of the tubular portion in an axial direction, and joining the semi-tubular bodies to each other with side surfaces of their respective connecting portions facing each other to form the tubular portion;
• and
• injecting a thermoplastic resin containing fillers for injection molding into an entirety of the regions corresponding to the coupling portions and the tubular portion to form the coupling portions integrated with the metal rings and integrate the coupling portions with the tubular portion.