Bottle and bottle cap device thereof

A bottle and a bottle cap device thereof are provided. In the bottle cap device, the outer-cap outer ring is threadedly connected with the inner-cap outer ring, the outer-cap inner ring penetrates through the inner-cap inner ring, the lower end of the outer-cap inner ring protrudes for a distance from the inner-cap inner ring, and the guide tube is arranged to extend in the outer-cap inner ring. The distance is sufficient to allow the end cap to be connected with the lower end of the outer-cap inner ring in a releasably sealing manner, and when the outer-cap outer ring is turned toward the loosening direction, the distance is sufficiently shortened to allow the end cap abutting with the inner-cap inner ring; while the end cap is connected with the inner-cap inner ring, the guide tube is connected with the end-cap hole, such that a stockage space is formed.