A switching regulator circuit for supplying two input potentials to a passive device that is driven by a potential difference between the two input potentials irrespective of potential differences between the two input potentials and a ground potential, includes: a low-voltage input terminal for receiving a lower input potential that is lower one of the two input potentials; a coil provided between the low-voltage input terminal and the passive device in series; and a switching device, provided between the low-voltage input terminal and the passive device to be in series with the coil, for making the coil generate a potential higher than the lower input voltage by repeatedly switching whether or not a current is allowed to flow in the coil, so as to supply the generated potential to the passive device.