When receiving a change of property information that is a key for performing property information integration, a FCMDB refers to the information stored in a property management information DB. Then, when property information that is a key after change is identical with the property information before change in the same configuration item, the FCMDB maintains the property information of the property information DB with respect to the configuration item. On the other hand, when the two property information data are not identical to each other, the FCMDB integrates property information for each configuration item on the basis of the key after change and registers the result in a property information storage unit.