An image processing device includes: an acquisition unit configured to acquire image data generated by an imaging element where each of narrow band filters constituting a predetermined array pattern is disposed at a position corresponding to any one of a plurality of pixels; a determination unit configured to determine whether or not a light amount of the invisible light range under an environment at the time when the imaging element generates the image data is larger than a threshold value; and a generation unit configured to generate vital information of a subject based on the determination result of the determination unit.