In an adjustment step, an adjustment purpose toner image is formed on an intermediate transfer belt, and the adjustment purpose toner image is removed from the intermediate transfer belt by a cleaning member contacting the intermediate transfer belt and through an electrostatic cleaning step. This adjustment step is executed in a state where a toner attachment amount on a charging member is switched from a first limit value, which is allowed in the image forming step to a second limit value, which is allowed immediately before executing the adjustment step. This switching is performed by the execution of a toner discharging step, where a power supply changes the state of applying voltage to the charging member from that in the electrostatic cleaning step, so that toner attached to the charging member is transferred to the intermediate transfer belt.