Device for discriminating spermatozoa labeled with at least one fluorochrome, which device comprises a transport channel, into which a solution containing said labeled spermatozoa can circulate in a predefined transport direction, excitation means (4; 4') allowing the stimulation of fluorescence emission of the labeled spermatozoa circulating in said transport channel, means for detecting the fluorescence emitted by the labeled spermatozoa circulating in said transport channel, and electronic processing means for discriminating labeled spermatozoa circulating in the transport channel from the fluorescence detected by the means of fluorescence detection, said device comprises one and/or the other of the following technical characteristics (a), (b): (a) said transport channel comprises a main plane of symmetry parallel to the transport direction, and a cross section in a plane (X, Z) perpendicular to the transport direction, which is symmetrical, which is characterized by a main axis of symmetry and has a maximum cross-sectional dimension, measured along this main axis of symmetry, and a minimum cross-sectional dimension, smaller than the maximum cross-sectional dimension, and measured along a secondary cross-sectional axis perpendicular to the main axis of symmetry, the fluorescence detection means comprising at least first detection means (50; 51), which are able to detect the fluorescence emitted by the spermatozoa in a direction substantially perpendicular to the principal plane of symmetry of the transport channel, and more particularly at least in a direction perpendicular to the main plane of symmetry of the transport channel, (b) said device comprising means for transporting the spermatozoa one behind the other in the transport channel with substantially the same spatial orientation of each spermatozoon, the fluorescence detection means comprising at least first detection means (50; 51) which are oriented in the direction of one of the two main faces having the largest surface of each spermatozoon successively passing in the transport channel in front of said detection means and being spatially-oriented, and the device being characterized in that the electronic processing means are able to automatically discriminate the spermatozoa using at least the duration of each fluorescence signature (PEAK) that is characteristic of a spermatozoon in the fluorescence detection signal generated by the first detection means (50; 51). (a) said transport channel comprises a main plane of symmetry parallel to the transport direction, and a cross section in a plane (X, Z) perpendicular to the transport direction, which is symmetrical, which is characterized by a main axis of symmetry and has a maximum cross-sectional dimension, measured along this main axis of symmetry, and a minimum cross-sectional dimension, smaller than the maximum cross-sectional dimension, and measured along a secondary cross-sectional axis perpendicular to the main axis of symmetry, the fluorescence detection means comprising at least first detection means (50; 51), which are able to detect the fluorescence emitted by the spermatozoa in a direction substantially perpendicular to the principal plane of symmetry of the transport channel, and more particularly at least in a direction perpendicular to the main plane of symmetry of the transport channel, (b) said device comprising means for transporting the spermatozoa one behind the other in the transport channel with substantially the same spatial orientation of each spermatozoon, the fluorescence detection means comprising at least first detection means (50; 51) which are oriented in the direction of one of the two main faces having the largest surface of each spermatozoon successively passing in the transport channel in front of said detection means and being spatially-oriented, and the device being characterized in that the electronic processing means are able to automatically discriminate the spermatozoa using at least the duration of each fluorescence signature (PEAK) that is characteristic of a spermatozoon in the fluorescence detection signal generated by the first detection means (50; 51).