An image forming apparatus for communicating with a management apparatus for storing a plurality of electronic prepaid information and authentication information related to the plurality of electronic prepaid information, and replaying to inquiry request for electronic prepaid information based on authentication information through a portable communication terminal storing authentication information. The image forming apparatus may include a connector to which the portable communication terminal is connected, a communication section for controlling the portable communication terminal and controlling communication with the portable communication terminal, a reading section for reading authentication information out of the portable communication terminal, an inquiry request section for sending authentication information and requesting the management apparatus to inquire the electronic prepaid information, a receiving section for receiving the electronic prepaid information, and an image forming control section for controlling whether to perform image processing.