To reflect modification performed in an upper hierarchy quickly onto the entire network by providing a form table listing the information of an overlay form distributed to the network and informing the registered form information upon request.

A form server 100 fetches a form table from a host form server 102 and compares it with the form table of overlay form stored in itself. If the form tables differs from each other, the form server 100 transmits a transfer request of modified form to the form server 102. Upon receiving the transfer request, the host form server 102 transmits the entity of overlay form and a form data to the form server transmitting the transfer request. Upon receiving a modified overlay form, the form server 100 registers the form and updates the form table thus maintaining the form.