A binder composition for a secondary battery includes: a water-soluble thickener (A) having a hydroxy group or a carboxy group; a cross-linking agent (B) having a functional group reacting with the hydroxy group or the carboxy group of the water-soluble thickener (A); and a particulate polymer (C). The particulate polymer (C) has a functional group reacting with the cross-linking agent (B) and includes an aliphatic conjugated diene monomer unit and an aromatic vinyl monomer unit. The binder composition contains 0.001 part by mass or more and less than 100 parts by mass of the cross-linking agent (B) and 10 parts by mass or more and less than 500 parts by mass of the particulate polymer (C), each per 100 parts by mass of the water-soluble thickener (A).