PURPOSE: A connection apparatus combining to a bottle neck including a separate connection device for helping the combination is provided to enable users to apply the connection apparatus to bottles with different sizes. CONSTITUTION: A connection apparatus combining to a bottle neck comprises the following: a mouth unit(2) formed on the upper side of the apparatus; a screw thread unit(4) formed on the lower side, including screw threads with the constant size on the inner surface including a first screw thread(5) and a second screw thread(6); and the bottle neck(200) having screw threads corresponding to the shape of the screw threads formed on the mouth unit.
