An imaging unit captures an image of a visual field. A detector detects a position of an eyeball and a sight line of an occupant. A visual point identifier identifies a position of a visual point of the occupant in the visual field, the eye position and the sight line direction. A measuring unit measures a position and a distance of an object included in the image of the visual field. An image generator generates display images based on the eye position and the position and the distance of the object. The display images are displayed on a virtual plane, fused on a fusion plane and displayed as a three-dimensional display on the visual field. The display images are generated to display the three-dimensional image at a given magnification ratio calculated by reducing a geometric display magnification ratio as the distance from the occupant increases.