Image forming method and apparatus therefor

An image forming method using an image forming apparatus, the apparatus including: a rotary image carrier, and a rotary intermediate transfer medium arranged in pressure-contact with the image carrier, wherein at least one of the image carrier or the intermediate transfer medium is a belt-shape rotary body which is looped over a group of rolls and can circulate with at least one of the rolls as a drive transmission roll, and the peripheral length of the belt-shape rotary body is m (m: integer)-times as long as the peripheral length of the drive transmission roll, the method including the steps of: a toner image forming step of rotating the image carrier at a constant peripheral speed to form the toner image successively for each color component on the image carrier; a toner image intermediate transfer step of rotating the intermediate transfer medium at a constant peripheral speed different from the constant peripheral speed of the image carrier, on condition that one revolution time of the intermediate transfer medium is n (n: integer or 1/integer)-times as long as one revolution time of the image carrier, to transfer the toner image for each color component carried on the image carrier; and a toner image final transfer step of collectively transferring the toner image for each color transferred on the intermediate transfer medium onto a recording medium.