Collecting log data efficiently by controlling the capturing event for an operation log on the basis of application layer information. A web server generates a response including an operation log capturing script and the information from an operation log capturing control definition table and a property capturing definition table, and sends the response to a client. In the client, the received information is forwarded from a web browser module to a script engine module. An operation log capturing module sets the information acquisition event handler on the basis of the forwarded information, captures a sequential operation log on the basis of the operations performed by a user in the web browser, and sends the captured sequential operation log to a log server. A log server module collects sequential operation log in an operation log table, and a log analysis module analyzes the collected logs.