There is provided a structure to make the setting of a criterion for eliminating noises easy in the scanning molecule counting method. In the inventive optical analysis technique of detecting light of a light-emitting particle in a sample solution, time series light intensity data of light from a light detection region detected with moving the position of the light detection region in the sample solution is generated, and a signal of a light-emitting particle individually is detected in the time series light intensity data, wherein a signal having a light intensity in a light intensity range set based upon a signal generation frequency integrated value distribution which is a distribution, obtained by using as a variable an intensity of a signal, of integrated values of generation frequencies of signals having an intensity not lower than the variable is extracted as the signal of the light-emitting particle.