To provide a release agent composition for molding and vulcanizing a tire capable of remarkably increasing the number times of tire molding and vulcanizing using the same bladder and capable of remarkably reducing the defective rate of the tire, and a tire molding bladder using the same.

The release agent composition for molding and vulcanizing the tire contains organopolysiloxane latex prepared by the emulsion polymerization of 100 pts.mass of cyclic diorganopolysiloxane, diorganopolysiloxane containing silanol groups at both terminals thereof or a combination of them (A), and 5-30 pts.mass of specific mercapto group-containing alkoxysilane, specific mercapto group-containing cyclic polysiloxane or a combination of them (B) in the presence of 0.1-15 pts.mass of an emulsion polymerization catalyst (C), 0.1-15 pts.mass of an emulsifier (D) and 80-500 pts.mass of water (E). The tire molding bladder coated with the release agent composition for molding and vulcanizing the tire is also disclosed.