An image forming apparatus that performs fixing processing on a sheet having a transferred toner image in smaller area units than the size of the sheet includes an image forming unit that forms a toner image in each predetermined color, a transfer unit that transfers the toner image in each color over a sheet, a detecting unit that detects, for each of the areas, the maximum number of stacked toner images, a determining unit that determines the amount of heat to be applied to the area based on the maximum number of stacked toner images of the area detected by the detecting unit, and a fixing unit that, on each of the areas on the sheet after the transfer processing by the transfer unit, applies the amount of heat determined by the determining unit and fixes a transferred toner image in each color.