A biometric information detecting apparatus includes a bio-signal measurer including a light-emitting unit and a light-receiving unit, the light-emitting unit configured to emit an optical signal and the light-receiving unit configured to detect the optical signal that is modulated by a target object; a low-frequency signal obtainer configured to obtain a low-frequency signal from the bio-signal measured by the bio-signal measurer; and a signal processor configured to analyze biometric information from the bio-signal in response to determining that the low-frequency signal obtained from the bio-signal is within a reference range.