An image formation method includes: a first image formation misregistration correction processing that causes each image formation unit to form a misregistration amount detection pattern, obtains an image formation misregistration amount by detecting the patterns, and corrects an image formation misregistration based on the obtained image formation misregistration amount; comparison processing that compares a previous image formation misregistration amount with a latest image formation misregistration amount; and a second image formation misregistration correction processing that causes each image formation unit to form new misregistration amount detection patterns, obtains a new image formation misregistration amount by detecting the new patterns and corrects the image formation misregistration based on the obtained new image formation misregistration amount when receiving a new print job and if a difference between the previous image formation misregistration amount and the latest image formation misregistration amount is larger than a predetermined value.