A charging device includes a long electrode, a cleaning member, a timing device, a drive source, a load measuring device, and a control device. The drive source moves the cleaning member in the outward direction for a first time period after the outward passage time and then reverses the cleaning member in the homeward position. The load measuring device measures driving load imposed on the drive source while the cleaning member is being moved. The control device controls motion of the drive source to turn the cleaning member from the outward direction to the homeward direction at a predetermined objective point near the second end, based on sum of driving loads imposed on the drive source while the cleaning member is being moved from the first point to a second point located along the outward direction.