Abstract: Multiple output power source apparatus enables to optimize efficiency for each output and to perform simultaneous shutdown and synchronous oscillations between the outputs. Power source circuits of various types connected to a power source are provided, and those power source circuits have a function of outputting an abnormality signal to other power source circuits when an abnormality occurs in the own circuit and shutting down the operation of the own circuit by an abnormality signal from other power source circuits and a function of outputting a synchronous oscillation signal synchronized with a switching oscillation frequency used for controlling the own circuit to other power source circuits and conducting synchronous control of the switching frequency used for controlling other power source circuits.