Provided are a novel binder for a secondary battery including a copolymer containing specific repeating units, and a binder composition for a secondary battery including the binder for a secondary battery and a compound containing an amine group and a hydroxyl group. When the binder for a secondary battery or the binder composition for a secondary battery is applied to a negative electrode and a secondary battery, expansion of the negative electrode is effectively suppressed, and the charge/discharge cycle characteristics and the performance of the secondary battery are significantly improved. Furthermore, the binder for a secondary battery has improved coatability and adhesion to effectively suppress the exfoliation and desorption of the negative electrode, thereby improving the performance of the secondary battery.