Patent ID: 7611027

Claim:
A bottle cap that is detachably assembled with an adjacent portion of an opening of a bottle, the bottle cap comprising: a circumferential portion that is shaped to wrap up an outer surface of the adjacent portion of the opening therein; a cap portion that closes an upper side of the circumferential portion; a plurality of tamper indication portions respectively extended from a central area of the circumferential portion to a lower end thereof, which is cut off as the bottle cap is opened; a bending portion that connects upper ends of the respective tamper indication portions in a line; an opening piece portion comprised of the plurality of tamper indication portions and the bending portion; a recess portion so formed on an inner surface of the circumferential portion on a position over the bending portion as to prevent separation; an opening knob protruding outward of an outer surface of the opening piece portion, the opening knob being configured to be capable of being moved upward by a thumb of user's one hand while the user's one hand is grasping the bottle; and a supporting protrusion that is so formed above the opening piece portion on the outer surface of the circumferential portion as to be contacted with the opening knob of the opening piece portion while the opening piece portion is moved upward by a cutting of the tamper indication portion, wherein, as the user moves the opening knob upward by the thumb of the user's one hand grasping the bottle, the tamper indication portion is cut off and then the opening knob is contacted with the supporting protrusion, whereby the use can open the bottle cap with a single hand.