Provided is an oxygen concentration device which, as an oxygen concentration device having a reduced difference in flow rates of gas which flows through a pressure equalization valve of a pressure equalization path during a purge step and a pressure equalization step, is provided at at least one end side of the pressure equalization valve with a pressure control member having a difference in pressure loss due to the direction of gas flow so that pressure loss of the gas which flows through the pressure equalization path in one direction becomes nearly equal to that of the gas which flows therethrough in the opposite direction.
