Provided is an imaging device (1) including: an imaging element (10); and a semiconductor element (20, 30) provided to be opposed to the imaging element and electrically coupled to the imaging element. The semiconductor element includes: a wiring region (20A, 30A) provided in a middle portion and a peripheral region (20B, 30B) outside the wiring region; a wiring layer (22, 32) having a wiring line in the wiring region; a semiconductor substrate (21, 31) opposed to the imaging element with the wiring layer interposed therebetween and having a first surface (Sa, Sc) and a second surface (Sb, Sd) in order from a side of the wiring layer; and a polishing adjustment section (23, 33) including a material that is lower in polishing rate than a constituent material of the semiconductor substrate, the polishing adjustment section being disposed in at least a portion of the peripheral region and provided in a thickness direction of the semiconductor substrate from the second surface.