To provide a method of measuring motile sperm concentration (MSC) in a semen sample.

Provided are: disposing a sample in a transparent container between a light source and a photodetector, modulating transmission light by movement of sperms in the sample, and thereby generating a waveform of analog voltage signals; generating a plurality of signal samples by sampling the signals; selecting signals satisfying a requirement by a waveform selection procedure; calculating absolute values of the respective signal samples satisfying the requirement; calculating an average of the absolute values; and calculating motile sperm concentration (MSC) based on the average value a.