PROBLEM TO BE SOLVED: To surely prevent contained liquid from permeating to a filter in a plug structure for a various kinds of liquid containers before the container is used for the first time, to improve usability for users in the first-time use by allowing the container to open with a dispensing operation of the contained liquid only, and to reduce a dispensing resistance when the container is used for the second time and thereafter.SOLUTION: A plug member integrally includes a base part 35a attached to a plug holder 31 to be mounted on a spout of a container, a plug body 34 fitted into a fitting part 31c formed in an intermediate part of a dispensing path of the plug holder 31, and an elastic connecting part 35b connecting the plug body 34 with the base part 35a elastically. The dispensing path is closed by the plug member until the container is used for the first time. When an internal pressure of the container is increased by squeezing the container in the first-time use, the plug body 34 is separated from the fitting part 31c so that the dispensing path is opened all the time thereafter.【課題】 各種の液体容器の口栓構造において、初回の使用前に内容液がフィルターまで滲み出てしまうことを確実に防止するとともに、内容液の吐出操作のみで開封させることができるようにしてユーザーの初回使用時の利便性を向上し、さらに、2回目以降の使用時の吐出抵抗を低減させる。 【解決手段】 容器の口部に装着される栓ホルダー31に取り付けられる基部35aと、栓ホルダー31の吐出路の中途部に設けた嵌合部31cに嵌合する栓体34と、該栓体34と基部35aとを弾性的に接続する弾性接続部35bとを一体に備える栓部材によって、初回の使用時迄は吐出路を閉止しておき、初回使用時に容器をスクイズすることで内圧が上昇すると、その内圧によって嵌合部31cから栓体34を離脱させ、それ以降は吐出路が常時開放されるようにする。【選択図】 図1
