PURPOSE: To provide more comfortable touch screen operation for an unspecified operator by making the operators precisely recognize an intended position.

CONSTITUTION: When the operator comes to before a touch screen part 1, a height detecting means 2 detects data corresponding to the view point position of the operator. When the operator presses down a desired input item position on an image displayed on a touch screen part 1, a calculating means 4 calculates the position that the operator intends on the image displayed at the display part from characteristic data stored in a storage means 3, the data which are detected by the height detecting means 2 and correspond to the view point of the operator, and operator's depression position data. Further, a 1st and a 2nd input item are displayed at height-directionally different positions at the touch screen part 1 and the position that the operator intends can be calculated from 1st and 2nd operator's depression position data corresponding to them.