To provide a blood drawing container for blood for determining a physiologically active matter in a blood cell derived by the blood cell, the container being capable of storing the drawn blood for a long time without giving unnecessary stimulus until the determination is carried out, and a method of accurately determining the physiologically active substance in the blood cell, and a method of accurately determining the function of the blood cell.

This blood container, whose inner pressure is reduced, is for determining a physiologically active matter in a blood cell derived by the blood cell, and the quantity of endotoxin when sampled by drawing a quantity of endotoxin-free water equal to the quantity of the liquid to be determined corresponds to the quantity not to derive the physiologically active substance in the blood cell. Also, the method of determining a blood cell function is to react the drawn blood using the blood drawing container and the stimulant in a reaction container and to determine the physiologically active substance derived into the blood cell.