Provided is a binder for battery electrodes which includes a polymer including: structural units (1) derived from a (meth)acrylate monomer (A) having a hydroxyl group; structural units (2) derived from a polyfunctional (meth)acrylate monomer (B); and structural units (3) derived from a reactive surfactant (C). This binder is used to prepare electrodes, and produce batteries such as lithium ion secondary batteries. Provided are: an aqueous binder which has a low environmental impact, exhibits excellent binding properties, and, notably, does not cause oxidation degradation under an electrode environment; and an electrode and a battery which use said binder.