A toner replenishing device includes a toner conveyance path for connecting a toner storing device with a developing device, a toner conveying device for conveying the toner from the toner storing device to the developing device along the toner conveyance path, and an air supplying device connected to the toner conveyance path vie an air supply path for supplying the toner storing device with air from a bottom of the toner storing device so as to agitate the toner pooling in the toner storing device.