A cosmetic vessel of a cosmetic product, includes a vessel body, a plug packing fitted into an upper portion of the vessel body, and a cap threadably engaged to the upper portion of the vessel body. The plug packing has a plurality of L-shaped walls provided by predetermined intervals at a lower portion thereof, a plurality of vent holes formed between the L-shaped walls, and a passage hole with a predetermined diameter and extended to the L-shaped walls to allow a brush-ended shaft of the cap to be placed into or removed from the vessel body. The cap includes a closing part mounted on a bottom thereof and having a hollow interior, a shaft extending downwardly from the closing part with an upper end fitted in the hollow interior of the closing part, and a brush provided to a lower end of the shaft.