A toner supply apparatus includes a first toner container; a first feeding member for feeding toner in the first toner container; a second toner container for receiving the toner from the first toner container; a second feeding member for feeding toner in the second toner container; a third toner container, detachably mountable relative to a main assembly of the toner supply apparatus, for receiving in the toner from the second toner container; wherein when the toner is supplied into the third toner container, the first feeding member is driven in accordance with a toner supply amount, and the second feeding member is substantially continuously driven irrespective of the toner supply amount.