A semiconductor apparatus for power supply control includes the following. A voltage control transistor is connected between a voltage input terminal and an output terminal. A control circuit controls the voltage control transistor according to an output feedback voltage. A first external terminal is supplied with an output control signal to control output voltage is input. The control circuit further includes the following. A first error amplifier outputs a voltage according to an electric potential difference between a voltage divided by a first voltage dividing circuit which divides the output voltage of the output terminal and a predetermined reference voltage. An output changing circuit displaces the reference voltage input in the first error amplifier or the voltage divided by the first voltage dividing circuit according to a voltage input in the first external terminal to change the output voltage to a voltage according to the output control signal.