An image forming device includes an image forming unit forming an image on a sheet with an image forming property, a pattern forming unit forming a pattern on an object, a detection value determining unit determining a first detection value representing the image forming property of the image forming unit through detecting the pattern formed on the object by the pattern forming unit, a storage unit storing thereon the first detection value determined by the detection value determining unit, a correction value determining unit determining a correction value for correcting the image forming property with the first detection value stored on the storage unit and a second detection value that has previously stored on the storage unit, and a control unit controlling the image forming unit to form the image with the image forming property corrected based upon the correction value determined by the correction value determining unit.