The present invention provides an air battery using oxygen in air as a cathode active material, the air battery comprising: a cylindrical anode made of a metal; a cathode constituted by a co-continuous body having a three dimensional network structure formed by an integrated plurality of nanostructures having branches; and a separator that is arranged between the cathode and the anode and absorbs an electrolytic solution, wherein: the cathode is arranged inside the anode via the separator; and the anode has an open hole that reaches the separator and constitutes a housing of the air battery.