PROBLEM TO BE SOLVED: To provide a biological tissue collection bag that can surely pass through only a small incision hole.SOLUTION: The biological tissue collection bag 1 having flexibility includes: an openable/closable opening 2 and a storage part 3 of a first diameter. The biological tissue collection bag 1 also includes a contraction member arranged along the periphery of the storage part 3, which contracts the storage part 3, in which the opening 2 is closed after the completion of storing a biological tissue X, to a second diameter smaller than the first diameter.
