To provide a bottle cap capable of supplying consumers with bottled beverage constituted of raw material and liquid while maintaining the freshness at the time of manufacture so that the material will not deteriorate, etc., and capable of smoothly mixing the material and the liquid.

The bottle cap 1 is provided with a fixed part 2 and a movable part 3 mutually removably screw-connected. The fixed part comprises a fitting part 2a for an opening part 11a of a bottle 11, which is used for supporting the movable part 3, and a through hole 2b on the axis X. The movable part 3 is provided with an intermediate stopper part 4 protruding from one of its surfaces, 3a, onto the axis through the through hole. The intermediate stopper part 4 comprises a housing chamber 5 for a raw material 12 and a pressure gas 13. An opening face 5a at the other end of the housing chamber is sealed by a tight plug 6. A plug opening means 7 is intermediately located between the tight plug and the fixed part, so that the tight plug is opened by the plug opening means at the time of relative movement of the fixed part and the movable part.