A modulation pattern calculation apparatus includes an iterative Fourier transform unit, a filtering process unit, and a modulation pattern calculation unit. The iterative Fourier transform unit performs a Fourier transform on a waveform function including an intensity spectrum function and a phase spectrum function, performs a replacement of a temporal intensity waveform function based on a desired waveform after the Fourier transform and then performs an inverse Fourier transform, and performs a replacement to constrain the phase spectrum function after the inverse Fourier transform. The filtering process unit performs a filtering process of cutting a part exceeding a cutoff intensity for each wavelength, on the intensity spectrum function in a frequency domain.