To stably generate a pattern even when light is radiated at least two or more times to continuously generate the same pattern.

A pattern generation method is disclosed in which, based on transmitted pattern information, laser beam is radiated from a laser beam source to a micromirror device in which a plurality of individually tilted micromirros are arranged in a matrix, and by reflected light in the micromirror device, a prescribed pattern is generated on the irradiation object of the light. In the method, when the laser beam is intermittently repeatedly radiated from the laser beam source to the micromirror device at least two or more times to continuously generate the same pattern, till the radiation frequently of the laser beam reaches the preset prescribed frequency, every time the laser beam is radiated from the laser beam source, pattern information same as the pattern information transmitted immediately before is transmitted to the micromirror device.