PURPOSE: To suppress the swelling of a blood corpuscle component even when the blood corpuscle component is preserved over a long period of time by preserving the blood corpuscle component under a gaseous atmosphere whose oxygen volume ratio is made lower than that of air.

CONSTITUTION: The opening part 2 of a bottomed tube body 1 is closed by a sealing member 3. The sealing member 3 is constituted of the film member 4 fixed to the peripheral edge of the opening part 2 in a releasable manner and the re-sealing rubber member 5 provided to the center of the outer surface thereof. Gas 6 is sealed in the tube body 1 in a low pressure state. The ratio of oxygen in the gas to the total volume of the sealed gas (oxygen occupying ratio) is 5% or less in a state of 1 atm and 25°C. Further, the gas 6 desirably contains inert gas, for example, nitrogen gas. Even after blood 7 is collected in the tube body 1 and a blood collecting needle is pulled out from the sealing member 3, the gas 6 is only returned to an atmospheric state from the low pressure state and generates no change in its oxygen occupying ratio. When a blood corpuscle component is preserved in a low oxygen concentration state, the swelling thereof can be suppressed over a long period of time.