Disclosed is a container (1) which can protect a freezing bag (2) filled with biological tissue and which can appropriately cool and heat the freezing bag (2). The container (1), which is substantially rectangular parallelepiped-shaped, is for containing the freezing bag (2) filled with biological tissue and for appropriately cooling and warming the freezing bag (2). The container (1) includes: at least one opening (10) formed in a side surface of the container (1)； and at least two ridges (11) which are formed at an inner surface of the container (1) and which form an air gap between the inner surface and the freezing bag (2).
