A scan conversion device includes a first buffer unit, a pixel packing unit, a second buffer unit, and a scan output unit. The first buffer unit stores therein pixel signals of the input image on every line in a main scanning direction thereof. The pixel packing unit groups N (N≧2) pixel signals on each line into pixel signal packs according to a predetermined pixel combination rule, and outputs them sequentially. The second buffer unit stores therein the pixel signal packs and aligns them in a second main scanning direction different from the main scanning direction. The scan output unit sequentially outputs the pixel signal packs aligned in the second main scanning direction. According to this configuration, a scan pattern of the input image is changed into a scan pattern of outputting every N output lines in the second main scanning direction.