A blood analyzer comprising: a flow cell configured to flow a measurement sample containing blood cells; a first light source configured to irradiate light of a first wavelength on the measurement sample flowing through the flow cell; a second light source configured to irradiate light of a second wavelength which is different from the first wavelength on the measurement sample flowing through the flow cell; a first light receiving part configured to receive a first scattered light obtained by irradiating light from the first light source on the blood cells flowing through the flow cell; a second light receiving part (131b, 132a) configured to receive a second scattered light obtained by irradiating light from the second light source on the blood cells flowing through the flow cell; and a processing unit configured to obtain values related to the number of red blood cells and the number of white blood cells based on a first scattered light information based on the signals output from the first light receiving part, and a second scattered light information based on the signals output from the second light receiving part, characterized in that the processing unit is configured to obtain, for each red blood cell, the hemoglobin concentration and the red blood cell volume from the first scattered light information and the second scattered light information using conversion information which defines the relationship of the combination of the first scattered light information and the second scattered light information, and the combination of the red blood cell volume and the hemoglobin concentration. a flow cell configured to flow a measurement sample containing blood cells; a first light source configured to irradiate light of a first wavelength on the measurement sample flowing through the flow cell; a second light source configured to irradiate light of a second wavelength which is different from the first wavelength on the measurement sample flowing through the flow cell; a first light receiving part configured to receive a first scattered light obtained by irradiating light from the first light source on the blood cells flowing through the flow cell; a second light receiving part (131b, 132a) configured to receive a second scattered light obtained by irradiating light from the second light source on the blood cells flowing through the flow cell; and a processing unit configured to obtain values related to the number of red blood cells and the number of white blood cells based on a first scattered light information based on the signals output from the first light receiving part, and a second scattered light information based on the signals output from the second light receiving part, characterized in that the processing unit is configured to obtain, for each red blood cell, the hemoglobin concentration and the red blood cell volume from the first scattered light information and the second scattered light information using conversion information which defines the relationship of the combination of the first scattered light information and the second scattered light information, and the combination of the red blood cell volume and the hemoglobin concentration.