An image forming device to perform an auto color registration. The image forming device includes a print unit capable of performing a print job in accordance with a plurality of print modes, a color registration processing unit to perform an auto color registration (ACR), a storage unit to store color registration conditions for the respective print modes, and a control unit to control the color registration processing unit to perform the ACR in accordance with the color registration condition corresponding to the present print mode of the print unit. The color registration condition may be at least one of a color registration execution period, a color registration execution time, and a color registration pattern. According to the image forming device, the proper ACR can be performed by print modes.