Toner contained in a toner container is used for replenishing a developing unit via an intermediate hopper. A toner sensor detects emptiness for the toner on an upstream side of a conveyance screw of the intermediate hopper in terms of the toner conveyance direction. Every time the toner sensor detects emptiness, the controller drives a rotation mechanism so that the toner is ejected from the toner container. Based on a drive history of a conveyance-purpose motor, the controller calculates a toner conveyance amount conveyed from the intermediate hopper between a time when the toner sensor detects emptiness and a time when the toner sensor detects emptiness again. When the calculated toner conveyance amount has been equal to or smaller than a first conveyance amount threshold value successively, the controller determines that the toner container is in a nearly empty state.