To enable the flow speed of anode gas to be optimal at a reaction part even when a separator is molded by press in order to increase productivity through reduction of the number of parts, miniaturization, and cost reduction.

This battery is provided with two flat electrodes with an anode 22 and a cathode 23, plural cells 31 made of flat electrolytic plate 21 pinched between these electrodes, and a separator 28 pinched between the plural cells 31 and is constituted. The separator 28 is formed with its continuous recess and protrusion in the waveform shape, the separator 28 is provided with an anode gas flow path 29 opened toward the anode 22 side and a cathode gas flow path 30 opened toward the cathode 23 side, and a ceramic particle 36 is accommodated in the anode gas flow path 29.