A controller for the storage apparatus: creates a second logical volume in a storage area provided by one or more storage devices; stores management information of a snapshot of a first logical volume, which is to be provided to a host computer, in the second logical volume; and reads the management information of a necessary snapshot from the second logical volume to a memory when needed, executes processing using the read management information, and returns the management information, which becomes no longer necessary, from the memory to the second logical volume. When reading the management information of the necessary snapshot from the second logical volume to the memory when needed, the controller changes the number of generations and address range of the snapshot of the management information to be read to the memory according to a generation and address of the snapshot whose management information is required.