An authentication checking server makes user authentication checking when an access is made to an individual in-house server. A resource managing server receives a resource request corresponding to the resource of the individual server, calculates the access right to the corresponding resource based on the resource request and the result of the authentication checking, and relays the calculated access right and the resource request to the individual server. Upon receipt of the access right and the resource request, the individual server transmits the resource as a mobile code. A client machine receives and executes the mobile code, whereby an encryption access is made to the resource of the individual server included in an in-house network via the relay agent generated within the client machine.