LEUKOCYTE CONCENTRATION SEPARATION DEVICE, BLOOD COLLECTION CONTAINER, AND METHOD FOR SEPARATING LEUKOCYTES

Provided is a blood collection container with which a specimen with a high leukocyte recovery rate and a small amount of contaminating erythrocytes can be obtained. A blood collection container according to the present invention is a blood collection container by which a predetermined amount of blood is collected, the blood collection container including:a blood collection container main body; anda hemocyte separation material contained in the blood collection container main body,the hemocyte separation material having a specific gravity at 25°C of 1.075 or more and 1.093 or less, andthe blood collection container including:a configuration of including a hemagglutinating agent contained in the blood collection container main body (configuration A2); ora configuration of including an osmotic pressure regulator contained in the blood collection container main body, and when a water-soluble component contained in the blood collection container main body is dissolved with physiological saline in an amount equal to a predetermined amount of blood to be collected in the blood collection container to obtain a solution for osmotic pressure measurement, the solution for osmotic pressure measurement having an osmotic pressure of 300 mOsm/L or more and 500 mOsm/L or less (configuration B2).