A method and an apparatus to remove a noise from an electrocardiography (ECG) sensor signal are provided. A noise removing method includes: receiving a sensor signal collected by an electrocardiography (ECG) sensor; extracting an ECG estimation signal from the sensor signal based on a peak value of the sensor signal; determining a first comparison value between the ECG estimation signal and a first reference signal indicating an average form of ECG signals; and classifying the ECG estimation signal as one of an ECG signal and a noise by comparing the first comparison value to a first threshold value.