A blood analyzing method to determine the presence of Plasmodium falciparum, comprising: irradiating light on a measurement sample prepared using fluorescent dye so as to produce a difference in fluorescence intensity between reticulocytes and mature red blood cells in a blood sample; detecting, using a flow cell, scattered light and fluorescent light given off from blood cells in the measurement sample, and obtaining fluorescence data related to the fluorescent light and scattered light data related to the scattered light for each blood cell; preparing a scattergram based on the scattered light data and the fluorescent light data; determining (S209, S210) the presence of Plasmodium falciparum parasites in the blood sample when distribution conditions of blood cells in a reticulocyte distribution range considered to contain reticulocytes in the scattergram are satisfied, when: the proportion of blood cells having a fluorescence intensity below a threshold in the reticulocyte distribution range is greater than a first preset threshold value, and/or the difference between a value reflecting a first centroid position based on the scattered light data in the reticulocyte distribution range and a value reflecting a second centroid position based on the scattered light data in the mature red blood cell distribution range considered to contain red blood cells is equal to or less than a second preset threshold value. irradiating light on a measurement sample prepared using fluorescent dye so as to produce a difference in fluorescence intensity between reticulocytes and mature red blood cells in a blood sample; detecting, using a flow cell, scattered light and fluorescent light given off from blood cells in the measurement sample, and obtaining fluorescence data related to the fluorescent light and scattered light data related to the scattered light for each blood cell; preparing a scattergram based on the scattered light data and the fluorescent light data; determining (S209, S210) the presence of Plasmodium falciparum parasites in the blood sample when distribution conditions of blood cells in a reticulocyte distribution range considered to contain reticulocytes in the scattergram are satisfied, when: the proportion of blood cells having a fluorescence intensity below a threshold in the reticulocyte distribution range is greater than a first preset threshold value, and/or the difference between a value reflecting a first centroid position based on the scattered light data in the reticulocyte distribution range and a value reflecting a second centroid position based on the scattered light data in the mature red blood cell distribution range considered to contain red blood cells is equal to or less than a second preset threshold value. the proportion of blood cells having a fluorescence intensity below a threshold in the reticulocyte distribution range is greater than a first preset threshold value, and/or the difference between a value reflecting a first centroid position based on the scattered light data in the reticulocyte distribution range and a value reflecting a second centroid position based on the scattered light data in the mature red blood cell distribution range considered to contain red blood cells is equal to or less than a second preset threshold value.