An apparatus for manufacturing stiffness-taper tubing includes a die having an extrusion hole, a die holder for holding the die, and a mandrel mounted inside the die holder and that fits in the extrusion hole. The apparatus forms stiffness-taper tubing by switching between and supplying resins having different stiffnesses over the mandrel from a plurality of resin-supply ports formed in the die holder such that the stiffness gradually changes in the lengthwise direction. A mandrel insertion hole connecting to the extrusion hole is formed in the die holder and the mandrel is mounted in this mandrel insertion hole. The plurality of resin-supply ports open to a cylindrical space formed between the inner surface of the mandrel insertion hole and the outer surface of the mandrel at a position separated from the extrusion hole in the die, and the plurality of resins flow together in this space.