A printing cost charging method of a printing system wherein the printing system includes a mobile terminal, an image forming apparatus capable of communicating data with the mobile terminal, and a server capable of communicating data with the mobile terminal via a wireless communication network. The printing cost charging method comprises the steps of transmitting printing data from the mobile terminal to the image forming apparatus, transmitting printing information relating to the printing data from the image forming apparatus to the mobile terminal, transmitting the printing information from the mobile terminal to the server, and controlling the server to charge a printing cost to the mobile terminal based on the printing information. Costly equipment and potential errors are reduced as the server of the printing system which charges the printing cost interfaces with the mobile terminal without the Internet.