A method for analyzing blood cells includes: preparing a measurement specimen for classifying white blood cells, by mixing a sample with a reagent in order to hemolyze red blood cells contained in the sample and to fluorescently stain nucleic acid in white blood cells contained in the sample; detecting, by flowing the prepared measurement specimen in a flow cell, fluorescence emitted from each blood cell in the measurement specimen and two types of scattered light at respective different angles, and obtaining a fluorescence signal and two types of scattered light signals; and classifying the white blood cells into at least four groups and detecting neoplastic lymphocytes, by performing analysis using at least three types of parameters based on the obtained fluorescence signal and two types of scattered light signals.