A light control device 1 includes a light source 10, a prism 20, a spatial light modulator 30, a drive unit 31, a control unit 32, a lens 41, an aperture 42, and a lens 43. The spatial light modulator 30 is a phase modulating spatial light modulator, includes a plurality of two-dimensionally arrayed pixels, is capable of phase modulation in each of these pixels in a range of 4π, and presents a phase pattern to modulate the phase of light in each of the pixels. This phase pattern is produced by superimposing a blazed grating pattern for light diffraction with a phase modulation range of 2π or less and a phase pattern having a predetermined phase modulation distribution with a phase modulation range of 2π or less.