A method of feeding a composite molten resin capable of easily forming a multi-kind-multi-layer preform. An apparatus for feeding the composite molten resin has a nozzle portion which includes an outer discharge port in which an outermost annular flow path through which a main layer-forming molten resin flows, meets an outer annular flow path through which a sub-layer-forming molten resin flows inside of the outermost annular flow path; and an inner discharge port in which a shell layer-forming molten resin annularly flowing inside of the outer conflux path, meets the core layer-forming molten resin flowing inside the shell layer; the outer discharge port and the inner discharge port being arranged in this order from the downstream toward the upstream in a direction in which the molten resins flow; wherein provision is made of a shaft-like opening/closing valve for opening and closing the inner discharge port, and a gear pump for intermittently discharging the sub-layer-forming molten resin.