Provided are a communication system for an in-vehicle communication apparatus mounted in a vehicle, and the in-vehicle communication apparatus included in said communication system. The in-vehicle communication apparatus communicates with a certificate information issuing system which creates electronic certificate information, and acquires certificate information from a sub-server apparatus. The in-vehicle communication apparatus makes a request to the sub-server apparatus to create the certificate information, and the sub-server apparatus creates the certificate information in response to the request. The in-vehicle communication apparatus then makes an inquiry to the sub-server apparatus regarding the creation status of the certificate information. Upon receipt of the inquiry, the sub-server apparatus makes a response indicating whether or not creation of the requested certificate information has been completed, and if the creation of the certificate information has been completed, the sub-server apparatus transmits the created certificate information to the in-vehicle communication apparatus together with the response.