An image forming apparatus includes a main processor, a first memory, a sub processor, and a second memory. The second memory stores a snapshot that includes an executable program obtained by loading one or more programs in the first memory. The main processor switches from a drive mode to a stop mode. The sub processor activates the main processor in response to any one of a plurality of activation factors being detected, cuts off power in response to an operation mode being switched to the stop mode, and supplies power to the main processor and the first memory before the main processor is activated. The main processor reads out a snapshot associated with an activation factor from the second memory and stores the snapshot into the first memory in response to being activated by the sub processor.