A bio signal measuring apparatus is provided which includes a sampling unit, and a processing unit. The sampling unit samples a portion of a pulse included in a pulse signal penetrating a person to be measured, and portions sampled from a plurality of pulses included in the pulse signal are different from each other. The processing unit processes a sampled signal and measures a bio signal of the person to be measured based on at least one of a center frequency, a bandwidth, or amplitude of a reconstruction pulse obtained through the sampling.