An image forming apparatus, comprising: a) communication means for communicating with an information terminal through a network; b) a monitor including a touch panel capable of accepting a multi-touch operation, for displaying an operation screen of said image forming apparatus; and c) a control means for controlling an operation of said image forming apparatus, wherein said control means is configured to: c-i) transmit an inquiry signal (600, 700; 102) about an operation method using the operation screen displayed on said monitor to said information terminal through said communication means, c-ii) receive through said communication means, operation method instruction information including information transmitted by said information terminal based on the inquiry signal (600, 700; 102) for indicating said multi-touch operation, c-iii) check an input format of the touch panel and an input format of the information terminal and, in a case where the input formats are different, convert the operation method instruction information based on the input format of the information terminal so as to conform to the input format of the touch panel, and c-iv) cause said monitor to display said operation screen and an operation instruction based on said operation method instruction information. a) communication means for communicating with an information terminal through a network; b) a monitor including a touch panel capable of accepting a multi-touch operation, for displaying an operation screen of said image forming apparatus; and c) a control means for controlling an operation of said image forming apparatus, wherein said control means is configured to: c-i) transmit an inquiry signal (600, 700; 102) about an operation method using the operation screen displayed on said monitor to said information terminal through said communication means, c-ii) receive through said communication means, operation method instruction information including information transmitted by said information terminal based on the inquiry signal (600, 700; 102) for indicating said multi-touch operation, c-iii) check an input format of the touch panel and an input format of the information terminal and, in a case where the input formats are different, convert the operation method instruction information based on the input format of the information terminal so as to conform to the input format of the touch panel, and c-iv) cause said monitor to display said operation screen and an operation instruction based on said operation method instruction information. c-i) transmit an inquiry signal (600, 700; 102) about an operation method using the operation screen displayed on said monitor to said information terminal through said communication means, c-ii) receive through said communication means, operation method instruction information including information transmitted by said information terminal based on the inquiry signal (600, 700; 102) for indicating said multi-touch operation, c-iii) check an input format of the touch panel and an input format of the information terminal and, in a case where the input formats are different, convert the operation method instruction information based on the input format of the information terminal so as to conform to the input format of the touch panel, and c-iv) cause said monitor to display said operation screen and an operation instruction based on said operation method instruction information.