An image forming device in which a plurality of nozzles are aligned in a designated alignment direction, wherein a plurality of pixels constituting a formed image includes dot omission pixels continuous in a scan direction by a defective nozzle included in the plurality of nozzles, and neighboring pixels within a designated distance in the alignment direction from the dot omission pixels, the image forming device comprising a pattern determining unit configured to determine a dot pattern after supplementation formed on neighboring pixels within designated range based on at least the number of dots to be formed on the pixels within the designated range including a portion of the dot omission pixels and a portion of the neighboring pixels according to recording data before supplementation of dots by the defective nozzle, and a pattern forming unit configured to form the dot pattern after supplementation.