Fish sex discrimination equipment and method comprising an automatic supplying unit, a light projection and reception detection unit, a discrimination control unit, a discharge unit, and a first conveyor and a second conveyor, and also comprising the steps of automatically supplying fish to be discriminated, transmitting light to a genital gland area of the fish, scanning the light, discriminating the sex of the fish based on the quantity of light tramsmitted, for example, a mean value or integrated value, and discharging the fish through the first or second conveyor which corresponds to the sex of the fish.