An image forming apparatus is provided with a controller that determines whether a first toner image to be firstly transferred to a transfer body has a portion that is not superimposed by a second toner image to be subsequently transferred to the transfer body so as to be superimposed on the first toner image to generate a determination result, and controls a transfer bias supplied to a transfer device that causes the second toner image to be transferred to the transfer body and an amount of toner to be adhered to form the second toner image, respectively, based on the determination result.