VEHICLE-MOUNTED DISPLAY CONTROLLER, VEHICLE-MOUNTED DISPLAY UNIT, DISPLAY CONTROL METHOD, CONTROL PROGRAM, AND RECORDING MEDIUM

The state of a vehicle rear portion such as the state of a rear seat or the like and the state of a vehicle rear side are allowed to be easily grasped at a driver's seat, and also the state of a vehicle front side is allowed to be easily grasped at a rear seat. An in-vehicle display device 10 is equipped with a camera 13, plural monitors 12, 21, an image pickup direction detector 24 for detecting the image pickup direction of the camera 13 and outputting an image pickup direction signal, and a controller 22 for selecting any one of plural monitors 12, 21 on the basis of the image pickup direction signal, and displaying the pickup image of the camera 13 on the selected monitor.