Provided is a technology for measuring a user's blood pressure by using light sources, in which the blood pressure measuring apparatus includes: a light emitter configured to emit one or more lights having different penetration characteristics toward a user; a light receiver configured to receive the lights that have penetrated through the user, and acquire photo-plethysmography (PPG) signals from the received lights; and a blood pressure measurer configured to measure a phase difference between the acquired PPG signals, and measure a blood pressure based on the measured phase difference.