An air cell includes a positive electrode layer, an electrolyte layer stacked on the positive electrode layer, a negative electrode layer stacked on the electrolyte layer and an electroconductive liquid-tight ventilation layer stacked on the positive electrode layer, the electroconductive liquid-tight ventilation layer being positioned on the opposite side of the positive electrode from the electrolyte layer. The assembled battery is provided with a plurality of the air cells described above. The assembled battery is provided with a flow path through which oxygen-containing gas flows interposed between the electrically-conductive liquid-tight ventilation layer of a first air cell and the negative electrode layer of a second air cell adjacent to the first air cell. The first air cell is electrically connected to the negative electrode layer of the second air cell via the electrically-conductive liquid-tight ventilation layer.