A power-source potential control circuit has: an output terminal outputting a control signal to a power-source generating device which generates a power-source potential in accordance with the control signal; an input terminal connected to an output of the power-source generating device; and a control unit configured to make a comparison between a trimming potential depending on a first potential at the input terminal and a predetermined reference potential and to output the control signal corresponding to a result of the comparison. In a trimming operation mode, the control unit changes the trimming potential in accordance with the result of the comparison.