To provide a compact inside rear view mirror device with a built-in imaging device, configured to detect foreign objects deposited on a windshield of a vehicle and to image surroundings of the vehicle.

The inside rear view mirror device with a built-in imaging device is provided with: a stay member 301 fixed in a vehicle 100; a casing part 302 supported rotatably by the stay member 301 and covering a reflection mirror 303 while exposing a reflecting face 303a; and a casing part 304 fixed by the stay member 301 and housing an imaging device 201. The imaging device 201 has at least two light sources irradiating light toward a windshield 105 of the vehicle 100, an imaging element having a plurality of pixel arrays, an imaging lens condensing incident light from a windshield 105 to the imaging element, and an optical filter disposed between the imaging lens and the imaging element. A focal point of the imaging lens is set farther than a position of an outer wall surface 105b of the windshield 105.