According to an input operation by input means (1), control means (4) causes display means (2) to display an electronic chart. The input means (1) is composed of a plurality of input keys arranged within a predetermined area. The display means (2) can display an input item selection column which can be selected by operating one of the input keys of the input means (1). The control means (4) can select the item displayed in the input item selection column of the display means (2) by the operation of the input key of the input means (1) and successively display an item required for the next input in the input item selection column.
