Abstract: Particle pattern images of the sample are optically measured by an image reader of a particle agglutination pattern judgment apparatus, and the measured particle pattern images are retrieved by a data processing controller to be able to execute pattern judgment processing. The data processing controller obtains predetermined parameters on the basis of the particle pattern images read by the image reader, and automatically judges an agglutination, non-agglutination, or unidentified attribute of each particle pattern on the basis of the obtained parameters. An operator visually observes the particle pattern images of the sample to visually determine an agglutination, non-agglutination, or unidentified attribute of each particle pattern of the sample. The operator inputs the visual judgment results in the particle agglutination pattern judgment apparatus using an input unit.