To provide a technique of trapping transition metal ions such as cobalt ions dissolved from positive electrode active material in a secondary battery to prevent deposition of transition metal on the negative electrode. Disclosed is a composition for non-aqueous secondary battery functional layer which contains organic particles containing an aliphatic conjugated diene monomer unit at an amount of 5% by mass or more based on the total monomer units in the organic particles, wherein the composition comprises the organic particles at an amount of 50% by mass or more in terms of solid content.