Abstract: A method and apparatus cancels an echo by using an echo replica generated such that a tap coefficient of an adaptive filter is sequentially updated, the echo being received from a transmitting end to a four-wire side through a two/four wire converter and being obtained such that a pulse signal having positive and negative polarities is fed into a receiving end, wherein a difference signal (error signal) between the echo replica and a reception signal is calculated; a correlation value between a signal representing a polarity of the error signal and a signal representing a polarity of the echo replica is calculated; when the correlation value is smaller than a predetermined value, a first of two types of tap coefficients which belong to each of a plurality of taps is updated based on at least the error signal and is set as the tap coefficient of the adaptive filter during a period in which the pulse signal is set in the positive polarity, and a second type of tap coefficient is updated based on at least the er