PROBLEM TO BE SOLVED: To provide a medical image storage apparatus in which management of key data used for encryption/decryption is easy, and by which medical image data desired by a user in a medical image file can be transmitted to an external device quickly.SOLUTION: In a medical image storage apparatus, a transmission/reception part 12 receives a medical image file containing a plurality of medical images. A dividing part 14 divides the data of each medical image into a plurality of partial files. An encryption processing part 17 encrypts the plurality of partial files by an encryption key common to the plurality of partial files. A partial file storage part 21 stores the plurality of encrypted partial files together with codes for identifying each medical image.