A imaging device includes: a spotlight emitting unit configured to emit two parallel spotlights; an imaging element configured to capture a measurement frame image having two spot areas irradiated with the spotlights and a plurality of first frame images which do not have the two spot areas, during capturing a moving image; and a controller configured to generate a grid image having a plurality of grid lines arranged at intervals set on the basis of the distance between the two spot areas in the measurement frame image, generate a plurality of second frame images by superimposing the grid image on the first frame images, and display the second frame images on a display unit.