Abstract: The object of the present invention is to provide an electrode material which enables the production of an electricity storage device that has a large discharge capacity, and suffers minimal voltage drop due to resistance even when discharge is performed at a large electric current; a method for producing the electrode material; and an electricity storage device that exhibits both high energy density and high output characteristics, and an electricity storage device is produced which uses, as an electrode, a polymer radical material-activated carbon-conductive material composite, prepared by adding dropwise, or pouring, a raw material solution, in which a polymer radical material having a radical partial structure in a reduced state is dissolved or swollen and an activated carbon and a conductive material are dispersed or dissolved, into a solution in which the polymer radical material, the activated carbon and the conductive material do not dissolve or swell, thus obtaining a precipitate containing the polym