To provide an oxygen concentrator equipped with a compressor, in which the rotation of a motor is almost fixed in any situations in a range from a hypoxia flow of about 0.5 L/min to a hyperoxia flow 7.0 L/min, at a low cost since the discharging flow of the compressor falls off as the inside of an adsorption tube is pressurized since the rotational frequency of the motor varies with variation in a power source or load fluctuation in conventional induction motors and on the other hand, since control becomes complicated, the composition parts of the motor also increase, and cost sharply increases although the rotational frequency decline can be prevented if rotational frequency control by a DC motor is performed.

The oxygen concentrator includes the compressor which compresses raw material air to generate compressed air and the adsorption tube, which stores an adsorbent material which adsorbs nitrogen from the compressed air, and uses a single-phase alternating current synchronous motor as a motor which composes the compressor.