In an SDN environment, data is migrated after checking whether the data conforms to a legal system of a migration destination. A control device changes a communication setting between first and second servers based on migration destination information and migration source information received from the first server and SDN setting data on a communication setting of the SDN stored in advance. The first server receives data on the legal system and determines whether the data conforms to the legal system to thereby determine whether the data can be migrated, or not. The control device executes a change in the communication setting when it is determined that the migration is enabled from the first server. The first server transmits data stored in a first storage unit to the second server according to the changed communication setting and the data is stored in a second storage unit.