Blocking a view of a whiteboard by a position of an attendee writing thereon is prevented, and writing records made by all attendees are stored to use the writing records including a course of the written records later. Each terminal of the attendees has a touch-panel-equipped terminal can divide any input line drawing on the terminal into line segment data, successively transmit the line segment data to the controller, and display line drawing information on the display of the touch-panel-equipped terminal. A liquid crystal projector having a controller that can be embedded therein or connected thereto is provided, the controller can sequentially record line drawing information transmitted from each touch-panel-equipped terminal in a data base, add the line drawing information to a video image memory of the whiteboard, and project the video image memory contents onto a wall surface while transmitting information of the data base to each touch-panel-equipped terminal.