A fluorescence profile of a chromosome indicates a distribution of fluorescence intensities along the chromosomein lengthwise. Chromosomes were extracted from cultured human HeLa cells and dyed with propidium iodide (concentration: 50mu g/ml). The profile of the chromosome flowing at the speed of 6m/s was measured by a new sorter by digitizing a time varying signal at 150ns per point. The measured profiles are resolved into A, B, C, D, E, F groups according to lengths of them and examples of profiles in individual groups are shown in figures. Profiles of dicentric chromosomes were measured well. The lengths of profiles correspond well with that of microscopic photographs of human chromosomes. Thus, the sorter is useful for detecting abnormal chromosomes and will be able to classify human chromosomes of No. 9 to No. 12.