Abstract: A bottle stopper for sealing and resealing a bottle neck. The bottle stopper includes a body, a plug and a jacket. The body includes legs and axially guiding grooves thereof provided on its inner circumference. The plug includes axially positioning ribs adapted to engage with the corresponding axially guiding grooves in order to increase reliability of the combined structure. A combined body and plug member is inserted into the jacket to form a bottle stopper. When the radially inner flange is engaged with the groove, the plug cannot be removed from the body. As the plug is axially pressed into the body, the radial inner flange is then disengaged with the groove, and the outer circumference of the jacket may radially expand to seal or to reseal a bottle.