Provided are a binder for a secondary battery, a negative electrode including the same, and a secondary battery including the same. More particularly, the binder for a secondary battery including a crosslinked product of a copolymer with a silane-based crosslinking agent according to the present invention may have excellent thermal resistance and mechanical properties and effectively improve a binding force, and the negative electrode for a secondary battery and the secondary battery including the same may effectively suppress expansion of a negative electrode to improve charge/discharge cycle characteristics and performance of the secondary battery.