A composite spout obtained by injection forming a spout body in a state where a sleeve having a functional resin layer disposed as an intermediate layer is fitted as a core onto the core member of an injection-forming metal mold such that the inner peripheral surface only of the sleeve is substantially exposed on the inner peripheral surface of the spout body. A tilted surface is formed on the inner peripheral surface at one end of the spout body in at least a portion thereof in the circumferential direction, the tilted surface being tilted outward in the radial direction from a position in agreement with the inner peripheral edge at the one end of the sleeve or from the inside thereof in the radial direction facing the one end of the spout body.