To provide a manufacturing method of an injection plug having a high degree of freedom of manufacture, superior in workability, and easy in maintaining accuracy; and a manufacturing method of a fuel injection valve having this injection plug.

Instead of a conventional manufacturing method of the injection plug for injecting fluid, this manufacturing method comprises an electrocasting processing process of making a part raw material being one long material by sticking metal by electrocasting processing to the periphery of a conductor having at least a conductive surface, an injection plug molding process of manufacturing the injection plug by molding the part raw material, and a conductor removing process of removing the conductor. A hole of removing the conductor is formed into an injection hole for injecting the fluid.