A live migration in a virtual computer system. On a source physical computer, the control information area of the source logical FC-HBA (managed by an OS) is copied to the control information area of a dummy logical FC-HBA managed by a hypervisor. After an FC login to the dummy FC-HBA, an address conversion table is rewritten so that a host physical address for referring to the control information area of a logical HBA1′ can be referred to using a guest logical address for referring to the control information area of the source FC-HBA. After the FC logout of the source FC-HBA, using a WWN of the FC used for the FC logout, a login to the destination logic FC-HBA is performed. Next, the OS on the source computer is taken over by the destination computer. Therefore, the disk accessed on the source computer can be accessed from the destination FC-HBA.