Provided is an image forming device which is capable of connecting an external storage device. After the external storage device has been connected to the image forming device, the image forming device performs a software installation based on setting data acquired from the external storage device. The image forming device stores a script for executing steps required for the executed software installation in ordered sequence in the external storage device. When the script has already been stored in the external storage device upon connection of the external storage device to the image forming device, the image forming device performs the software installation by implementing the steps in the ordered sequence in accordance with the script.