Abstract: Provided is a blood collection tube preparing apparatus which is simple, downsized, portable, capable of being easily placed on a desk or the like, excellent in responding to an emergency such as a disaster, and capable of preparing various kinds of blood collection tubes depending on a blood collection instruction from a doctor. A blood collection tube holding member is arranged along one transferring belt and between a forward-side transferring belt and a backward-side transferring belt of the one transferring belt, and lower end surfaces of a cap of a blood collection tube is supported on upper end surfaces of the blood collection tube holding member and the forward-side transferring belt. The forward-side transferring belt applies a transferring force to the blood collection tube through the cap. Further, the members constituting a storage box are accommodated in one module, and the storage box is detachably mounted onto a mounting portion of an apparatus main body.