A biosignal detecting apparatus and a method therefor are provided. The biosignal detecting apparatus includes a signal generator configured to generate a predetermined specific frequency signal, at least two transmit helix antennas configured to transmit circular polarizations according to the specific frequency signal to a subject, a receive helix antenna configured to receive a circular polarization including a biosignal reflected from the subject, a mixer configured to generate an intermediate frequency (IF) signal by mixing the received circular polarization with the specific frequency signal and a detecting unit configured to detect the biosignal of the subject from the IF signal.