To provide an imaging device capable of preventing the generation of a hunting operation by enabling proper judgement of switching between a color photographing mode and a black-and-white photographing mode.

The imaging device includes a filter unit 2 made of an infrared ray cutting filter 9 and a dummy glass 10 in an optical path between a photographing lens 1 and an imaging element 3. The imaging device has a color photographing mode and a black-and-white photographing mode. Further, the imaging device includes a CPU 6 as a judging means for judging switching between the color photographing mode and the black-and-white mode from a video signal.