A hematological analyzer, comprising: a measuring unit comprising: a laser source which irradiates laser light to a measurement sample comprising cells in a blood or a body fluid and a white blood cell measuring reagent; a first detector which is configured to detect Z side scattered light obtained from the cells; a second detector which is configured to detect side fluorescent light obtained from the cells; and a data processing unit configured to process a measurement result output from the measuring unit; wherein the body fluid is selected from a group consisting of cerebrospinal fluid, thoracic fluid, abdominal fluid, fluid of the cardiac sac, synovial fluid, dialysate from peritoneal dialysis, and intraperitoneal rinse; characterized in that the data processing unit is configured to: receive a designation of a measuring mode among at least a blood measuring mode and a body fluid measuring mode from a measurement mode setting means; classify white blood cells in the blood into a plurality of subclasses, the subclasses being neutrophils, lymphocytes, monocytes, eosinophils, and basophils, based on at least the intensity of the detected side scattered light and the intensity of the detected side fluorescent light, in the case that the data processing unit has received the designation of the blood measuring mode; and classify the cells in the body fluid into mononuclear cells, polymorphonuclear cells, and nucleated cells other than white blood cells, based on at least the intensity of the detected side scattered light and the intensity of the detected side fluorescent light, in the case that the data processing unit has received the designation of the body fluid measuring mode. a measuring unit comprising: a laser source which irradiates laser light to a measurement sample comprising cells in a blood or a body fluid and a white blood cell measuring reagent; a first detector which is configured to detect Z side scattered light obtained from the cells; a second detector which is configured to detect side fluorescent light obtained from the cells; and a data processing unit configured to process a measurement result output from the measuring unit; wherein the body fluid is selected from a group consisting of cerebrospinal fluid, thoracic fluid, abdominal fluid, fluid of the cardiac sac, synovial fluid, dialysate from peritoneal dialysis, and intraperitoneal rinse; characterized in that the data processing unit is configured to: receive a designation of a measuring mode among at least a blood measuring mode and a body fluid measuring mode from a measurement mode setting means; classify white blood cells in the blood into a plurality of subclasses, the subclasses being neutrophils, lymphocytes, monocytes, eosinophils, and basophils, based on at least the intensity of the detected side scattered light and the intensity of the detected side fluorescent light, in the case that the data processing unit has received the designation of the blood measuring mode; and classify the cells in the body fluid into mononuclear cells, polymorphonuclear cells, and nucleated cells other than white blood cells, based on at least the intensity of the detected side scattered light and the intensity of the detected side fluorescent light, in the case that the data processing unit has received the designation of the body fluid measuring mode. receive a designation of a measuring mode among at least a blood measuring mode and a body fluid measuring mode from a measurement mode setting means; classify white blood cells in the blood into a plurality of subclasses, the subclasses being neutrophils, lymphocytes, monocytes, eosinophils, and basophils, based on at least the intensity of the detected side scattered light and the intensity of the detected side fluorescent light, in the case that the data processing unit has received the designation of the blood measuring mode; and classify the cells in the body fluid into mononuclear cells, polymorphonuclear cells, and nucleated cells other than white blood cells, based on at least the intensity of the detected side scattered light and the intensity of the detected side fluorescent light, in the case that the data processing unit has received the designation of the body fluid measuring mode.