PURPOSE: To provide a heat source unit installation work device which can easily convey a heat source unit to an installation place through a narrow passage, stairs and an elevator.

CONSTITUTION: The device is provided with a frame body 2, which is detachably placed on the vertically liftable table of a lift carriage for conveyance, and a column 3 which is disassemblably erected on the frame body 2. On the rear face of the frame body 2, a horizontal first positioning pin 7 is projected. On the lower face of the frame body 2, a vertical second positioning pin 6 is projected. The column 3 is provided with a holding mechanism M which detachably hold a heat source unit. With the frame body 2 placed on the lifting table of a carriage, the first positioning pin 7 is locked to the lock hole provided in the rear end of the lifting table of the carriage, and the second positioning pin 6 is fitted in the vertical direction hole of the lifting table of the carriage.