PURPOSE: To manufacture a golf club shaft of fixed quality simply and efficiently in the case of a golf club shaft of fiber-reinforced resin.

CONSTITUTION: After injecting a molten resin, a pressurized gas is injected under pressure from a pressurizing port 2 at one end of a die cavity 4, then a spherical floating core 1 is pushed, and the molten resin is extruded from a discharge port 3 provided on the opposite side of the die cavity 4 to form a hollow part 5. Consequently, an extrusion molding can be prepared using an extrusion molding-based technique, so that a golf club shaft of fixed quality can be manufactured easily and efficiently.