A detector panel having therein an X-ray detector, a signal processing circuit for interface, and a battery for power supply, the detector panel includes a first signal processing circuit for processing the detection signals from the X-ray detector, a second signal processing circuit for processing the output signal from the first signal processing circuit, a first power supply circuit for adjusting the output voltage of the battery by means of switching regulation, to supply the output to the second signal processing circuit, a second power supply circuit for adjusting the output voltage of the first power supply circuit by means of switching regulation, to supply the output to the X-ray detector and the first signal processing circuit, and a switching circuit for switching the configuration of the second power supply circuit between a single connection of one linear regulator and a series connection of two linear regulator.