PURPOSE: To compact a machine room unit as much as possible and permit the miniaturization of the whole of a combined refrigerator by a method wherein a horizontal cooler is arranged in a cooler room and a cold air guiding duct as well as a return duct are provided along the wall surface of the machine room unit while a centrifugal fan for ventilating cold air is arranged in the beginning end of the cold air guiding duct.

CONSTITUTION: A heat insulative partitioning wall 8 is provided on the bottom of a cooler room 5 to partition and form a cold air passage 9 extending in the direction of fore-and-aft and the rear part of the cold air passage 9 is connected to a return duct 10 formed along the back wall 5a of the cooler room 5 while the fore part of the cold air passage 9 is connected to a suction port 11 formed on the partitioning wall 8 whereby the return duct 10 is communicated with the suction port 11 or the inside of the cooler room 5 through the cold air passage 9. A cooler 12 is fixed to the upper part of the partitioning wall 8. A cold air guiding duct 13 is provided in the shape of an arc along the back wall surface of a machine room unit 1 across the back wall 5a of the cooler room 5 and the back wall 6a of a compressor room 6 at the rear part of the cooler 12 while a centrifugal fan 14 for ventilating cold air is provided in the beginning end of the cold air guiding duct 13.