PURPOSE: To perform the correction processing quickly by managing integrally remote maintenance data by a host node and allowing each node to be corrected to only hold the correction level and to report this correction level to the host node.

CONSTITUTION: Information managed by a higher node, namely, a host node 1 are a list 21 of names of its suborginate nodes, lists 22 and 23 of names of goods (software names) installed in said nodes and their subordinate nodes, a list 31 of all goods, a list of correction data of individual goods, and actual correction data. When the lower node starts a remote maintenance program 4 omitted in the figure, the correction level of goods managed by this node is transmitted to the higher node and transmission of remote maintenance data is requested. The higher node receives it to compare it with information managed by this higher node, and correction data is transmitted in case of correction in this correction level and following levels.