According to one embodiment, a display device includes a substrate, a thin film transistor, a pixel electrode, an organic light emitting layer, a common electrode, and a sealing unit. A feature manifest stored by the second device is readable by the first device after the first device enters a commissioning process. The first condition is different than the second condition. A locking mechanism is provided by which the first coupling part can be connected to the second coupling part in at least two different positions, and the second coupling part is located at different depths in the opening in the two different positions. The battery ECU supplies the detected voltage to the HV ECU. Thus, the number of transistors per one memory cell can be reduced by two transistors, so that a storage capacity can be increased further.