In a vehicle-mounted navigation system, an operating unit that operates the driver's seat side image and an operating unit that operates the passenger's seat side image had to be provided separately, which increased the number of operation buttons and the size of the navigation system device. In a vehicle-mounted navigation system that displays images in multiple directions, an operating direction detector detects which direction an operation was performed from, and a controller controls the vehicle-mounted navigation system based on a detection result of the operating direction detector.