A spray gun, which contains: a coating liquid nozzle configured to discharge a coating liquid from an outlet; and a flow channel forming member configured to surround an outer perimeter surface of the coating liquid nozzle to form an air flow channel, through which atomizing air passes, between the outer perimeter surface of the coating liquid nozzle and the flow channel forming member, wherein the spray gun is configured to atomize the coating liquid with the atomizing air to spray the atomized coating liquid to a coating target, wherein a gap T of the narrowest part of the air flow channel is 0.48 mm or smaller, and wherein a ratio T/L of the gap T to a distance L from the narrowest part to an apical surface at which the outlet of the coating liquid nozzle is open is 0.60 or greater.