An image forming device includes a sheet carrying body carrying a sheet thereon in a predetermined direction, a pattern selecting unit selecting one of a plurality of patterns that includes a first pattern and a second pattern, the first pattern including a plurality of marks aligned at intervals of a predetermined distance within a first range, the second pattern including a plurality of marks aligned at intervals of a predetermined distance within a second range shorter than the first range, a forming unit configured to form the selected pattern on the sheet carrying body and form an image on the sheet being carried on the sheet carrying body, a deviation determining unit determining a positional deviation of the image based upon the pattern formed, and a correcting unit performing positional deviation correction for the image to be formed on the sheet based upon the positional deviation determined.