The present invention relates to a blood separation container for extracting self-platelet, and the container includes: a body having an internal space divided into an upper liquid chamber and a lower liquid chamber an upper cap for closing the upper liquid chamber a lower cap arranged with the outside peripheral surface thereof closely contacting the inside peripheral surface of the lower liquid chamber so as to rise upward a liquid collection part arranged between the upper liquid chamber and the lower liquid chamber having a central fluid passage protruding upward for making the upper liquid chamber communicate with the lower liquid chamber a first fastening means with the inside peripheral surface provided with a screw thread for engaging with a screw thread formed on the outside peripheral surface of the lower part of the body a detaching prevention member having a second fastening means with the inside peripheral surface provided with a screw thread with a smaller diameter than the first fastening means, the second fastening means communicating with the first fastening means and a rise member of bolt structure inserted in and engaging with the second fastening means, a part of the rise member being inserted into the inside of the lower liquid chamber of the body for moving upward the lower cap closely contacting the inside peripheral surface of the lower liquid chamber so as to vary the volume of the lower liquid chamber.La présente invention concerne un récipient pour séparation du sang permettant dextraire les plaquettes en vue dune auto-transfusion, le récipient comprenant : un corps possédant un espace interne divisé en une chambre supérieure pour liquide et en une chambre inférieure pour liquide un bouchon supérieur servant à fermer la chambre supérieure pour liquide un bouchon inférieur dont la surface périphérique externe est en contact étroit avec la surface périphérique interne de la chambre inférieure pour liquide afin de sélever vers le haut une
