IN-VEHICLE DISPLAY DEVICE, IN-VEHICLE DISPLAY DEVICE CONTROL METHOD, AND PROGRAM

An in-vehicle display apparatus has a display unit mounted on a mounting position of a rearview mirror in a vehicle cabin of a vehicle. The display unit includes an image displaying unit that displays an image taken by an imager mounted to the vehicle, and a half mirror disposed in front of the image displaying unit. The display unit changes an image to be displayed according to a lighting state of an interior lamp.