An apparatus for manufacturing an electricity storage material includes: a dissolving device that dissolves a thickener in a solvent; a viscosity adjusting device that adjusts viscosity of the solution of the thickener; a stirring device that mixes the solution of the thickener adjusted in viscosity and powder of an active substance to produce a first mixture, and stirs the first mixture to produce a second mixture; a heating device that heats the solution of the thickener or the first mixture by the time the stirring of the first mixture is started after the solution of the thickener is produced, so as to heat the solution of the thickener contained in the first mixture; and a kneading device that kneads the solution of the thickener and the powder of the active substance which are contained in the second mixture to produce a third mixture.