A toner cartridge guiding unit includes a guide frame to guide mounting of a toner cartridge, and having a toner feed hole formed opposite to a toner discharge hole of the toner cartridge, a toner sealing member attached to the proximity of the toner feed hole, and a lifting unit to raise the toner cartridge so that the toner cartridge does not interfere with the toner sealing member during mounting. Because the toner sealing member is not damaged by the repeated mounting and demounting of the toner cartridge, toner is supplied efficiently from the toner cartridge, without leaking towards the guide frame.