Abstract: An apparatus and method for analyzing particles includes a distribution data preparation device for measuring parameters that characterize particles contained in a specimen and for preparing a distribution data of the particles in a coordinate space based on the parameters, a judgement region storage device for storing in advance a predetermined judgement region in the coordinate space, a base point extraction device for extracting, when the distribution data forms at least one group, a group base point that shows a position of the group, a judgement region correction device for correcting a position of the judgement region in the coordinate space by referring to each group base point extracted every time a distribution data is prepared by the distribution data preparation device, and a judgement device for judging the specimen based on the particles present within the corrected judgement region.

Abstract: A method and apparatus for determining a particle criterion to set a predetermined region as the particle criterion in a distribution data of a particles of a specimen and to analyze the specimen based on particles which appear in the predetermined region, includes preparing first fundamental distribution data by accumulating each distribution data of a first specimen group which belongs to a first category, preparing second fundamental distribution data by accumulating each distribution data of a second specimen group which belongs to a second category, calculating a region on the distribution data where peculiar particles exist in the first or second category by comparing the first and second fundamental distribution data and establishing the calculated region as the particle criterion. The region may also be shifted if needed.