At the first display device 3, the following vehicle 48 may be displayed at the center auxiliary display area 32c of the first display device 3 of the front windshield 15 instead of the right auxiliary display area 32b thereof. In a case that the center rear camera is not mounted on the own vehicle, the following vehicle 48 is displayed at the center auxiliary display area 32c as a picture image not as a taken image. In another example, the following vehicle 48 may be displayed at the rearview mirror 25 as the third display device.