In an emphasis optimization device, a calculating unit calculates an inverse characteristic of an amplitude characteristic based on the amplitude characteristic of a transmission path, and an inverse Fourier transform unit performs an inverse Fourier transform on the inverse characteristic to obtain an impulse response. An extracting unit extracts, from the obtained impulse response, an impulse response corresponding to the number of taps necessary for emphasis to be added to a digital signal to be transmitted on the transmission path. An emphasis amount calculating unit converts the extracted impulse response into a value of the emphasis to calculate an emphasis amount.