PURPOSE: To allow perfuming of an oxygen enriched gas with perfumes of arbitrary kinds and concns. by branching the piping between an oxygen enriched gas inlet pipe and outlet pipe to two pipes, providing a flow rate control valve at one thereof and connecting plural openable/closable perfume containers in parallel to the other.

CONSTITUTION: The piping between the oxygen enriched gas inlet pipe 8 and the outlet pipe 12 is branched to the two pipes 9, 10. The flow control valve 11 is provided at one pipe 10 thereof and the plural perfume containers 1A, 1B, 1C each having an orifice on the inlet side and a stop valve on the outlet side are connected in parallel to the other pipe 9. The perfuming concn. can be adjusted by operating the flow rate control valve in the case of perfuming the oxygen enriched gas. The perfuming by selecting or combining the perfumes of arbitrary kinds is possible by properly opening and closing the stop valves on the outlet sides of the respective perfume containers 1A, 1B, 1C.