A double container pouring cap that can abut an air valve in an intended state and stably exhibit performance related to the air valve, and a double container includes: an air valve that can abut on and separate from a back surface of a cap body, and blocks air flow from a vent to an outside air inlet, while allowing air flow from the outside air inlet to the vent; and an inner plug provided to face the back surface of the cap body with the air valve interposed between, and including a regulation part that abuts on a part of the air valve and limits separation of the air valve from the back surface of the cap body. A first abutting surface of the air valve where the regulation part abuts is a flat surface.