[Object] To acquire distance information concerning a living tissue through an endoscope with higher accuracy irrespective of the diameter of the endoscope.
[Solution] An imaging device according to the present disclosure includes: a ranging light source section configured to output ranging light for measuring a distance at a predetermined timing; an image sensor on which an image of the imaging target is formed; a ranging light image sensor on which optical feedback of the ranging light from the imaging target is imaged; a branch optical system configured to coaxially branch incident light into three types of optical paths different from one another; and a distance information calculating section configured to calculate distance information concerning the imaging target on a basis of a result of detection of the optical feedback. In the branch optical system, a first optical path among the three types of optical paths is used as an optical path configured to guide the ranging light whose applied position on the imaging target has been controlled to the imaging target, a second optical path is used as an optical path configured to form an image of the imaging target on the image sensor, and a third optical path is used as an optical path configured to image the optical feedback on the ranging light image sensor. The distance information calculating section calculates a spaced distance to the imaging target by a Time Of Flight method on the basis of the result of detection of the optical feedback.