An input device of a multimedia board inputs lecturer-written information that a lecturer writes on a display page. An information processor sends the lecturer-written information input by the input device to a plurality of information terminals. A reader/writer of each of the plurality of information terminals reads out textbook information from a recording medium recording the textbook information representing contents of a textbook. A display device displays the read textbook information and the lecturer-written information supplied from the information processor, which are superimposed one on top of the other. The reader/writer records the textbook information and lecturer-written information, which are displayed by the display device, as a single file on the recording medium.