Provided are a platelet preparation-storing device and a platelet preparation-storing method capable of extending the storage period for platelet preparations. The platelet preparation-storing device (10) comprises a platelet preparation-holding unit (12) that holds platelet preparation storage containers (21) for storing platelet preparations and a three-dimensional clinostat (11) for rotating the platelet preparation-holding unit (12) around two axes. The platelet preparation-storing device (10) is capable of stirring the platelets in the platelet preparations in three dimensions uniformly with a constant load by rotating the platelet preparation-holding unit (12) in two axial directions. Because the platelet preparations can be stored while thereby limiting platelet aggregation, the quality of the platelet preparations can be maintained and the platelet preparation storage period can be extended.
