Abstract

A tamper-proof, bag-shaped container and straw is provided for drinking liquid contained therein. The container is formed by heat-sealing the edges of synthetic resin film sheets or paper sheets laminated with synthetic resin film. The container includes a straw heat-sealed between the sheets and in fixed contact therewith. The straw projects outwardly from the container at the upper end portion thereof and extends to the vicinity of the bottom of the container at the lower end thereof. A threaded cover is connected to a threaded upper end portion of the straw for screwing the cover on and off. The container includes a plurality of teeth, each having a guide side and a cut side. A frangible member is provided in the rotary path of the teeth and in the vicinity of the upper end portion of the straw. The frangible member is elastically deformed towards the guide side of the cover when screwing on the cover and is cut away upon contacting the cut side of the teeth when screwing off the cover.