A touch panel device includes a screen that has a plurality of display areas in a first layer, and a plurality of touch areas in a second layer. The second layer lies over the first layer. One touch area is superposed over one display area. The touch area is generally larger than the display area. A position of each touch area is slightly offset from the corresponding display area, depending upon a relative positional relationship between the touch panel device and a user of the touch panel device. The offsetting may be determined based on ergonomics in order to effectively prevent an erroneous operation of a user to the touch panel device. The user is a vehicle driver if the touch panel device is used in a car navigation machine.