A volume migration method for causing to carry out a migration from a first volume manager to a second volume, includes: by causing the first volume manager to carry out actual accesses, obtaining information of correspondence, by the first volume manager, between logical volume offsets and physical blocks on a physical medium; judging, based on the obtained information of the correspondence, whether or not an exceptional data layout is carried out; and when it is judged that the exceptional data layout is not carried out, updating only a header area on the physical medium for the second volume manager. Incidentally, the aforementioned obtaining is carried out by using a program module for blocking access by the first volume manager to the physical medium. Thus, when only the header area is updated after it is confirmed the exceptional data layout is not made, the high-speed volume migration becomes possible.