An oxygen saturation measuring apparatus is provided. The oxygen saturation measuring apparatus includes a sensor configured to detect motion of the oxygen saturation measuring apparatus, a light emitter comprising light emitting circuitry configured to emit light to a target subject, a light receiver comprising light receiving circuitry configured to receive one or more of light reflected by the target subject or light transmitted through the target subject to generate a signal, and a processor configured to filter a frequency component corresponding to the detected motion in the signal, to detect a pulse frequency from the filtered signal, and to determine oxygen saturation of the target subject using the filtered signal and the detected pulse frequency.