A stochastic processor of the present invention includes a fluctuation generator configured to output an analog quantity having a fluctuation, a fluctuation difference calculation means configured to output fluctuation difference data with an output of the fluctuation generator added to analog difference between two data, a thresholding unit configured to perform thresholding on an output of the fluctuation difference calculation means to thereby generate a pulse, and a pulse detection means configured to detect the pulse output from the thresholding unit.