A computer system regarding which there is no possibility that data loss or data leakage will occur caused by volume migration is provided.The computer system includes: a memory resource to be accessed by a host computer; a storage system for providing a volume, which logicizes the memory resource, to the host computer; and a management device for managing migration of the volume. When detecting a task of migration of the volume based on a request from a first administrator, the management device compares an encryption function setting status of the volume with the encryption function setting status of a migration destination object of the volume; and sends notice of this comparison result to a second administrator, who is different from the first administrator, for security management of the storage system.