A container (A) that prevents from an unauthorized opening and can be easily identified after being unauthorizedly opened, comprising: a casing including an opening and a first abutting edge surrounding the opening ; a cover selectively mounted onto the casing for closing the opening , wherein the cover has a second abutting edge laterally extending therefrom and abutting against the first abutting edge when the cover closes the opening ; a puller extending from the second abutting edge of the cover ; a snapping device formed between the casing and the puller , the snapping device including a plug formed on the puller and a socket defined in the casing for temporarily receiving the plug and holding the plug in place, a pre-broken line , wherein, when the puller is lifted and the cover is lifted from the casing , the plug is maintained in the socket and the pre-broken line is broken, characterized in that the pre-broken line is formed on the puller and surrounds a root of the plug and a weakened portion is formed on at least one place of the puller such that the puller is irreversibly curved after being lifted due to the weakened portion ; wherein the pre-broken line is separated from a periphery of the plug and the weakened portion is formed between the pre-broken line and the opposite sides of the puller ; wherein the puller forms a pull-tab and, when the puller is lifted, the puller is irreversibly curved after being lifted along the weakened portion and the pre-broken line , surrounding the plug , is broken; and the irreversibly curved puller is a basis for easily identifying whether the container (A) has unauthorizedly been opened or not. a casing including an opening and a first abutting edge surrounding the opening ; a cover selectively mounted onto the casing for closing the opening , wherein the cover has a second abutting edge laterally extending therefrom and abutting against the first abutting edge when the cover closes the opening ; a puller extending from the second abutting edge of the cover ; a snapping device formed between the casing and the puller , the snapping device including a plug formed on the puller and a socket defined in the casing for temporarily receiving the plug and holding the plug in place, a pre-broken line , wherein, when the puller is lifted and the cover is lifted from the casing , the plug is maintained in the socket and the pre-broken line is broken, characterized in that the pre-broken line is formed on the puller and surrounds a root of the plug and a weakened portion is formed on at least one place of the puller such that the puller is irreversibly curved after being lifted due to the weakened portion ; wherein the pre-broken line is separated from a periphery of the plug and the weakened portion is formed between the pre-broken line and the opposite sides of the puller ; wherein the puller forms a pull-tab and, when the puller is lifted, the puller is irreversibly curved after being lifted along the weakened portion and the pre-broken line , surrounding the plug , is broken; and the irreversibly curved puller is a basis for easily identifying whether the container (A) has unauthorizedly been opened or not. <EOS>