Electronic blackboard and accessories such as writing tools

The present invention discloses an electronic blackboard apparatus comprising an electronic blackboard portion (1), a writing tool (3), an eraser (4), an instruction rod (2), a position detection portion (11), a writing tool determination portion, a data processing portion (5), and an output portion (52). When image information such as characters or figures are drawn on the writing surface (14) of the electronic blackboard portion by using the writing tool, when the region which is intended to be erased of the information which is being displayed is selected by the eraser, or when an assignment is carried out by using the instruction rod, information representing the type of the tool which is being used selected from a group consisting of the writing tool, eraser and instruction rod and the predetermined information about the position are supplied to the data processing portion via the position detection portion or the writing tool determination portion whereby display information corresponding to the display information which has been subjected to a predetermined process or instruction information by means of the instruction rod are output to the output portion.