According to one embodiment, an image alignment adjusting apparatus includes: an endless traveling belt; a pattern sensor configured to detect an adjustment pattern including plural colors imaged on the traveling belt; and a correcting unit configured to use, in initial adjustment, for image alignment adjustment, an initial adjustment value obtained by detecting a plurality of sets of the adjustment patterns imaged over the entire circumference of the traveling belt and use, in intermediate adjustment, for the image alignment adjustment an intermediate adjustment value obtained by correcting the initial adjustment value using an intermediate detection value obtained by detecting one set of the adjustment pattern imaged on the traveling belt.