PROBLEM TO BE SOLVED: To provide a respiration gas supply apparatus capable of being downsized, the respiration gas supply apparatus being capable of supplying respiration gas adjusted to a desired oxygen concentration while securing an air flow required in taking in the outside air.SOLUTION: A respiration gas supply apparatus 101 comprises: an oxygen pipe 10 capable of being connected to an oxygen gas source an air pipe 20 communicating with the outside air and a mixture pipe 30 for sending mixture gas of compressed oxygen and air generated by connecting the oxygen pipe 10 with the air pipe 20. The air pipe 20 comprises: an outside air intake port 21 provided so as to be exposed to the outside a filtration filter 22 provided at the intake port 21 and air sending means 23 that is arranged on the downstream side of the intake port 21 to draw air from the intake port 21 to the inside through the filtration filter 22, the air sending means being capable of adjusting a flow rate of the air. The air sending means 23 includes a plurality of air blowers 23a, 23b arranged so that respective air sending directions of the air blowers are connected in series.SELECTED DRAWING: Figure 1
