To provide an image forming device which restores its state to be able to start image formation at optional time and also suppresses power consumed after the restoration until starting the image formation.

An image forming device 100 detects a temperature Te of a fixing unit 10 in the device 100 by a thermistor 20, and determines restoration required time Tx for restoring a low power state to a stand-by state based on the detected temperature Te. Until current time becomes equal to time calculated by subtracting the determined restoration required time Tx from start time Ts, the device 100 repeats determination of the restoration required time Tx, and when the current time Tn becomes the time calculated by subtracting the determined restoration required time Tx from the start time Ts, the device 100 outputs a signal to start a restoration operation.