A polymer compound for use as a binder for a negative electrode of an electrical storage device is formed by condensing polyacrylic acid and a multifunctional amine represented by the following formula (1), in which Y represents a straight chain alkyl group having 1 to 4 carbon atoms, a phenylene group, or an oxygen atom, and R1 and R2 each independently represent one or more hydrogen atoms, methyl groups, ethyl groups, trifluoromethyl groups, or methoxy groups.