A direct sound extraction device, comprising: a Fourier transform unit which performs a Fourier transform process on an input signal (L, R) that includes a reverberant sound in a direct sound signal (Ld, Rd) for transforming the input signal (L, R) from a time domain to a frequency domain and calculating frequency spectra of real and imaginary numbers, and transforms, on the basis of frequency spectra of real and imaginary numbers of the input signal (L, R), the input signal (L, R) to a first amplitude spectrum signal (Lfa, Rfa) and a phase spectrum signal (Lfp, Rfp); a low-pass filter unit which carries out a low-pass filtering process for each frequency on the first amplitude spectrum signal (Lfa, Rfa) by using a preset normalized cutoff frequency for generating a second amplitude spectrum signal; a first limiter unit which limits a negative side of an amplitude of the second amplitude spectrum signal on which a low-pass filtering process has been performed by the low-pass filter unit, so as to bring negative amplitude values to zero for generating a third amplitude spectrum signal; a first subtraction unit which subtracts the third amplitude spectrum signal whose negative-side amplitude has been limited by the first limiter unit from the first amplitude spectrum signal (Lfa, Rfa) for generating a fourth amplitude spectrum signal; a second limiter unit which limits a negative side of an amplitude of the fourth amplitude spectrum signal calculated by the first subtraction unit, so as to bring negative amplitude values to zero for generating a fifth amplitude spectrum signal (Lfd, Rfd); and an inverse Fourier transform unit which calculates, on the basis of the phase spectrum signal (Lfp, Rfp) and the fifth amplitude spectrum signal (Lfd, Rfd) whose negative-side amplitude has been limited by the second limiter unit, a signal that is made from frequency spectra of real and imaginary numbers, and performs an inverse Fourier transform process on the signal that has been made from frequency spectra of real and imaginary numbers to generate the direct sound signal (Ld, Rd) that is obtained by extracting a non-stationary signal from the input signal (L, R). a Fourier transform unit which performs a Fourier transform process on an input signal (L, R) that includes a reverberant sound in a direct sound signal (Ld, Rd) for transforming the input signal (L, R) from a time domain to a frequency domain and calculating frequency spectra of real and imaginary numbers, and transforms, on the basis of frequency spectra of real and imaginary numbers of the input signal (L, R), the input signal (L, R) to a first amplitude spectrum signal (Lfa, Rfa) and a phase spectrum signal (Lfp, Rfp); a low-pass filter unit which carries out a low-pass filtering process for each frequency on the first amplitude spectrum signal (Lfa, Rfa) by using a preset normalized cutoff frequency for generating a second amplitude spectrum signal; a first limiter unit which limits a negative side of an amplitude of the second amplitude spectrum signal on which a low-pass filtering process has been performed by the low-pass filter unit, so as to bring negative amplitude values to zero for generating a third amplitude spectrum signal; a first subtraction unit which subtracts the third amplitude spectrum signal whose negative-side amplitude has been limited by the first limiter unit from the first amplitude spectrum signal (Lfa, Rfa) for generating a fourth amplitude spectrum signal; a second limiter unit which limits a negative side of an amplitude of the fourth amplitude spectrum signal calculated by the first subtraction unit, so as to bring negative amplitude values to zero for generating a fifth amplitude spectrum signal (Lfd, Rfd); and an inverse Fourier transform unit which calculates, on the basis of the phase spectrum signal (Lfp, Rfp) and the fifth amplitude spectrum signal (Lfd, Rfd) whose negative-side amplitude has been limited by the second limiter unit, a signal that is made from frequency spectra of real and imaginary numbers, and performs an inverse Fourier transform process on the signal that has been made from frequency spectra of real and imaginary numbers to generate the direct sound signal (Ld, Rd) that is obtained by extracting a non-stationary signal from the input signal (L, R).