A processing device includes: a control-signal generating unit that generates a control signal by switching a predetermined potential and a second potential that is different from the predetermined potential; multiple processing units that, if a potential of the control signal is the predetermined potential, flow a predetermined current, process and outputs an input signal, and if a potential of the control signal is the second potential, do not flow the predetermined current and do not process a signal; and a control unit that controls the control-signal generating unit such that, in a case of an operating mode in which the processing units process a signal, the control signal is a voltage signal of the predetermined potential, and in a case of a standby mode in which the processing units do not process a signal, the control signal is a voltage signal of the second potential.