A component replacement support tool for a fusing unit with a roller that contains a lamp cartridge includes a roller insertion/removal guide shaft and a lamp protection member detachably housed in the roller insertion/removal guide shaft. The fusing unit includes a replacement opening via which the roller or the lamp cartridge can be removed from or inserted into the fusing unit along an axis of the roller for replacement. The roller insertion/removal guide shaft is inserted into the roller along the axis of the roller and fixed so as to guide the roller when the roller is removed from or inserted into the fusing unit via the replacement opening. The lamp protection member is inserted between the roller and the lamp cartridge when the lamp cartridge is pulled out of or inserted into the roller along the axis of the roller via the replacement opening.