An oxygen concentrating apparatus (10) has an oxygen concentrating unit (12), a compressor (26) for supplying compressed air to the oxygen concentrating unit (12) and a compressor housing (28) for accommodating the compressor (26). The compressor housing (28) includes a plurality of air inlet ports (28a) for introducing the air into the compressor housing (28) and an air outlet opening (28b) for discharging the air from the compressor housing (28). A cooling fan (30) is mounted on the compressor housing (28) at the air outlet opening (28b) for drawing the air from the compressor housing (28). The air inlet ports (28a) are disposed adjacent to the side wall of the compressor (26) to direct the air flow induced by the cooling fan perpendicularly to the side wall of the compressor (26). The capacity of the cooling fan (30) and the diameter of the air inlet ports (28a) are selected to ensure the velocity of the air flow through the air inlet ports (28a) is equal to or lower than 15m/sec. |