This blood analyzer includes a sample preparation portion preparing a first measurement sample containing a blood sample and a hemolytic agent and a second measurement sample containing the blood sample, the same hemolytic agent as the hemolytic agent and a staining agent and a control portion classifying white blood cells in the first measurement sample into at least four groups of monocytes, neutrophils, eosinophils and others on the basis of fluorescent information and two types of scattered light information generated by a light information generation portion and classifying blood cells in the second measurement sample into at least malaria-infected red blood cells and others on the basis of fluorescent information and scattered light information generated by the light information generation portion.