To change the screen angle of an on-vehicle display to the value capable of reducing the effect of the reflected light on an occupant when the solar beam is incident on the on-vehicle display.

When the solar beam is incident on a display unit 30, and the reflected light from the display unit 30 is irradiated over a predetermined range including the view point position E, the irradiation preventive screen angle to prevent irradiation of the reflected light over the predetermined range is calculated, and the screen angle of the display unit 30 is changed to the irradiation preventive screen angle. Thereby, irradiation of the reflected light over the predetermined range including the view point position E can be prevented, and the effect of the reflected light on an occupant can be reduced. When the solar beam is incident on the display unit 30, the screen angle of the display unit 30 can be changed to the screen angle to reduce the effect of the reflected light on the occupant thereby.