Provided are a joining portion in which a male threaded portion threaded to a container-side female threaded portion is formed; a connector main unit disposed at an inner side of the joining portion, sharing a center axis therewith, and is connected so as to be rotatable relative thereto; and a siphon tube attached to the connector main unit so as to extend toward the bottom portion of the container and has a tip curved in a substantially horizontal direction, wherein the joining portion is screwed in independently of the connector main unit when attaching the connector by using a securing jig that, by being inserted from above the connector main unit, causes depressed/protruding portions to be engaged, thus preventing relative rotation to each other, and by using a tightening jig that tightens the male threaded portion by being engaged at the upper surface of the joining portion.