The present invention provides a method of storing TAIC in which TAIC is prevented from suffering from freezing and solidification during storage thereof in the winter season. In the method of the present invention, the triallyl isocyanurate is mixed with a silane coupling agent to prepare a composition comprising both thereof, and the resulting composition is stored. In the preferred embodiment of the present invention, the silane coupling agent is used in an amount of 5 to 30% by weight based on the weight of the triallyl isocyanurate, and γ-methacryloxypropyl trimethoxysilane is used as the silane coupling agent.