An image forming apparatus includes a data storage device that stores list data, and a simple object access protocol (SOAP) processor. When a partial-list-data-request message is received from a client apparatus by a communication processor, the SOAP processor generates a response message including a partial list data items that have not been sent among the plurality of partial list data items that are generated by dividing the list data, and causes the communication processor to send the response message to the client apparatus. The client apparatus includes a SOAP processor that causes a communication processor to send the partial-list-data-request message to the image forming apparatus, and that, when the response message including the partial list data item is received from the image forming apparatus by the communication processor, extracts the partial list data item from the response message.