A data processing apparatus includes a first processor, a second processor, a first power source which performs electric power supply to the first processor, a second power source which preforms electric power supply to the second processor, a detector which detects an abnormality of the second power source, and a switcher which is capable of switching a power supply target of the first power source between the first processor and the second processor. When an abnormality of the second power source is detected, the first processor stops an operation of the first processor, and the switcher switches the power supply target of the first power source from the first processor to the second processor after the operation of the first processor is stopped.