A biosignal processing apparatus includes a communication interface configured to receive a biosignal, and a processor configured to set a target interval of the biosignal, calculate a quality metric corresponding to the target interval based on a target component that is a frequency component of the target interval corresponding to a set value and a non-target component that is a frequency component of the target interval not corresponding to the set value, and estimate a quality of the biosignal based on the quality metric.
