A signal processing apparatus feeding a frame of a signal in frequency domain of a reception voice signal into a sound echo canceler includes a first reception section for receiving frames of the reception voice signal in frequency domain before having a rate-of-speech change process applied; a second reception section for receiving frames of a signal in time domain having the rate-of-speech change process applied by units of frames; and a frequency-domain frame synthesis section for synthesizing a frame of the signal in frequency domain of the reception voice signal based on the signal in time domain having the rate-of-speech change process applied at a frame currently being processed by the signal processing apparatus, and a frame of the reception voice signal in frequency domain corresponding to the signal in time domain having the rate-of-speech change process applied.