An image forming device for forming an image on an image forming object by irradiating the image forming object with a luminous flux corresponding to the image, the image forming device including: a lens having a zoom lens and a focus lens; a driving system; a position sensor; a controlling circuit; and a memory. When the controlling circuit receives a first command, the controlling circuit sets the target values, controls the driving system using the set target values, and performs control to record the respective positions detected by the position sensor in timing of ending the controlling of the driving system in the memory as a first adjustment value. When the controlling circuit receives a second command to read contents of the memory, the controlling circuit reads the first adjustment value from the memory, and controls the driving system using the first adjustment value as the target values.