Centrifugal separation method

A centrifugal separation method, using a centrifugal separation container, which centrifugally separating a first specific gravity component and a second specific gravity component, of which a specific gravity of the second gravity component is higher than a specific gravity of the first specific gravity component, contained in a specimen injected into a storage space by rotating a container about a central axis of the container as a rotation axis, the centrifugal separation method comprising:

• injecting a specimen into a storage portion that forms the storage space in the centrifugal separation container,
• wherein the storage portion includes an inclined inner wall portion of which a diameter gradually decreases from an upper end toward a lower end thereof and the lower end is connected to a base portion, and
• a concave portion formed at a part of the inclined inner wall portion,
• the concave portion includes a concave portion side surface that is connected to a concave portion bottom surface with a width of the concave portion gradually decreases toward the concave portion bottom surface from the inclined inner wall portion;
• rotating the centrifugal separation container about the central axis of the container as a rotation axis,
• wherein an interface between the specimen centrifuged during rotation and air, in a radial direction with respect to the central axis crosses where the concave portion is formed.