An object of the present invention is to provide a display unit and a power save controller capable of reducing the power consumption in a power save mode. There are provided a power supply section 110 which supplies power to a display unit 100 connected to a computer main unit 200 to display images, a display section 120 which performs image display on the basis of an image signal, a power save control section 130 which controls, on the basis of a sync signal, an energization mode in which the power supply section 110 is in an on state and a power save mode in which the power supply section 110 is in an off state, and a power save termination determination circuit 140 which is driven by auxiliary power for peripheral devices supplied from the computer main unit 200, which substitutes as the power save control section 130 to make a determination on the basis of the sync signal as to whether or not a return from the power save mode to the energization mode should be made, and returns at least the power save control section 130 to the on state in the case of determining that a return to the energization mode should be made, and which has a power consumption lower than that of the power save control section 130.