To correct a displayed position even while traveling without performing troublesome correction work when the displayed position of a vehicle is different from an actual position.

A plurality of kinds of correction patterns stored in a brain wave processing part 71 in advance is compared with a correction pattern of a brain wave signal, whether the correction patterns agreed with each other exist or not, is determined, and whether the instruction of correction is appropriate or not is determined on the basis of the detected present position and the displayed present position when the agreed correction patterns exist. An image of the present position displayed in accordance with the instruction of correction is corrected when the instruction of correction is appropriate.