Patent ID: 8680485

Claim:
An optical analysis method which detects light from a light-emitting particle dispersed and moving at random in a sample solution using an optical system of a confocal microscope or a multiphoton microscope, comprising steps of: moving a position of a light detection region of the optical system in the sample solution by changing an optical path of the optical system; measuring light intensity from the light detection region with moving the position of the light detection region in the sample solution to generate light intensity data; and individually detecting a signal indicating light of a light-emitting particle on the light intensity data; wherein in the step of individually detecting a signal indicating light of a light-emitting particle, a signal which has an intensity exceeding a threshold value is detected selectively as a signal indicating light of the light-emitting particle and the threshold value is set so that a signal indicating light from a light-emitting particle encompassed in a region narrower than the light detection region in the light detection region is detected selectively.