A check rule for assuring system security is generated. A communication information monitoring apparatus includes a pseudo-client, a monitoring unit, and a unification unit. The pseudo-client transmits a request message containing a trace value as a parameter to a web application and analyzes a response message returned from the web application. The monitoring unit monitors whether the trace value transmitted by the pseudo-client is used in various positions in the system. The unification unit generates a check rule according to the processing result of the pseudo-client and the monitoring unit and a check policy registered in advance. The check policy contains the parameter use purpose and the process for the check processing.