A noise suppression apparatus using spectral subtraction is provided. A noise estimation unit estimates noise components included in a mixed signal. A fundamental frequency of the mixed signal is detected. A subtraction factor in the spectral subtraction is set based on the detected fundamental frequency. The spectral subtraction for the mixed signal is executed using the set subtraction factor and the estimated noise components. A boundary frequency at the fundamental frequency or a frequency lower than the fundamental frequency is set, and a subtraction factor for a frequency lower than the boundary frequency is set to assume a value larger than a subtraction factor for a frequency not less than the boundary frequency.