A sample analyzer for evaluating erythrocyte production status comprising: a detection unit configured to irradiate a biological sample with light and obtain scattered light information and fluorescent light information; a cell classification means configured to classify cells contained in the biological sample into cell groups including a reticulocyte group and a mature erythrocyte group based on the scattered light information and fluorescent light information, wherein the cells whose fluorescent light intensity is greater than a predetermined amount are classified into the reticulocytes group; a scattered light information obtaining means configured to obtain an average value (RET-Y) of scattered light intensities of reticulocytes included in the reticulocyte group ; and obtain an average value (RBC-Y) of scattered light intensities of mature erythrocytes included in the mature erythrocyte group ; characterized by a calculation means configured to calculate a value (RET-He) corresponding to an amount of hemoglobin contained in reticulocytes included in the reticulocyte group based on the average value (RET-Y) of scattered light intensities of reticulocytes; calculate a value (RBC-He) corresponding to an amount of hemoglobin contained in mature erythrocytes included in the mature erythrocyte group based on the average value (RBC-Y) of scattered light intensities of mature erythrocytes; and calculate a difference (Delta-He) between these values (RET-He, RBC-He) for being used as an indicator for evaluating erythrocyte production status; and by an output device configured to output the difference (Delta-He) calculated by the calculation means . a detection unit configured to irradiate a biological sample with light and obtain scattered light information and fluorescent light information; a cell classification means configured to classify cells contained in the biological sample into cell groups including a reticulocyte group and a mature erythrocyte group based on the scattered light information and fluorescent light information, wherein the cells whose fluorescent light intensity is greater than a predetermined amount are classified into the reticulocytes group; a scattered light information obtaining means configured to obtain an average value (RET-Y) of scattered light intensities of reticulocytes included in the reticulocyte group ; and obtain an average value (RBC-Y) of scattered light intensities of mature erythrocytes included in the mature erythrocyte group ; obtain an average value (RET-Y) of scattered light intensities of reticulocytes included in the reticulocyte group ; and obtain an average value (RBC-Y) of scattered light intensities of mature erythrocytes included in the mature erythrocyte group ; characterized by a calculation means configured to calculate a value (RET-He) corresponding to an amount of hemoglobin contained in reticulocytes included in the reticulocyte group based on the average value (RET-Y) of scattered light intensities of reticulocytes; calculate a value (RBC-He) corresponding to an amount of hemoglobin contained in mature erythrocytes included in the mature erythrocyte group based on the average value (RBC-Y) of scattered light intensities of mature erythrocytes; and calculate a difference (Delta-He) between these values (RET-He, RBC-He) for being used as an indicator for evaluating erythrocyte production status; and by an output device configured to output the difference (Delta-He) calculated by the calculation means . <EOS>