Provided is an oxygen concentration device which is provided with: a prediction means which predicts the device power-usage amount, and which serves as a control mechanism capable of sustaining battery-driven operation, even in cases when the power required by the oxygen concentration device on a commercial power supply temporarily exceeds the output power-supply capacity of a battery and a control means which, in cases when the power supply is switched to a rechargeable battery, and the power prediction value from the prediction means exceeds the output capacity of the rechargeable battery, restricts the rotational frequency of a compressor such that the power consumption of the compressor becomes equal to or less than the output capacity of the rechargeable battery.
