Provided is an image forming device that has a duplex printing function, and suspends execution of a printing operation to allow internal temperature to decrease when the internal temperature increases and reaches predetermined limit temperature at which toner in a developing unit is fusible, the image forming device storing, each time a print job is received, the received print job therein as a waiting print job; selecting, from among a plurality of waiting print jobs, a print job that is estimated to cause the smallest increase in the internal temperature as a print job to be executed preferentially, based on printing conditions set on the respective waiting print jobs; and controlling execution order of the waiting print jobs so that the selected print job is executed preferentially.