A battery device includes a photoelectric conversion device and a secondary battery. The photoelectric conversion device includes a first positive electrode, a first negative electrode, and a photoelectric conversion layer provided between the first positive electrode and the first negative electrode, the photoelectric conversion layer including an inorganic semiconductor and a pigment. The secondary battery includes a second positive electrode, a second negative electrode, and an electrolyte layer provided between the second positive electrode and the second negative electrode. Here, one of a first electrode pair and a second electrode pair is adhered directly, the first electrode pair including the first and the second positive electrodes, and the second electrode pair including the first and the second negative electrodes.