REAR-VIEW MIRROR DEVICE MOUNTED IN A VEHICLE, VEHICLE-MOUNTED DISPLAY DEVICE, VEHICLE-MOUNTED DISPLAY SYSTEM

A vehicle-mounted display device includes a glass plate including a first arcuate surface at a first outer circumferential edge part and facing a front surface side, a casing that supports the glass plate from a rear surface side and including a housing and a frame that projects therefrom, and a display unit stored in the casing. A rear surface of the glass plate and a front surface of the frame are spaced and face each other. The frame includes a projection that projects from the front surface of the frame toward the rear surface of the glass plate at a second outer circumferential edge part of the front surface of the frame. The projection includes a second arcuate surface and a center and a radius of the second arcuate surface that are identical to a center and a radius of the first arcuate surface, respectively.