Abstract: This invention is an easy opening case, when taking something (e.g. tape cassette) out of the case, it is enough to use a single hand to open it. Besides, the case has a function of preventing itself from being opened by mistake. It mainly consists of a positioning hook on one side of its cover, corresponding to the hook, there disposed a positioning block on the wall of the base, the positioning block is an "L" shaped, elastic, movable coupled moving lug; when the case is closed, the hook just retains the positioning block so as to have a function of preventing the cover from being opened by mistake. When it is open for a user to take out an object in it, it is enough to use a single hand to handle it; that is, use the thumb to push the coupled moving lug, and use other fingers to pull the cover so that the positioning hook can get off the positioning block and the cover can be easily opened by a single hand.