<p>Presented is technology that is useful for forming an accurate subject image on an imaging element and that can be applied in the assembly process of an optical system. The imaging device has an imaging element, a plate-like body to which the imaging element is attached, and a holding member for holding the plate-like body. The plate-like body is provided with a first section where at least one affixing hole is provided and a second section where at least one adjustment hole is provided. The plate-like body is held by the holding member using multiple affixing members that are each inserted through at least one affixing hole and at least one adjustment hole. When a first section is affixed to the holding member, the relative positions of a second section and the holding member are adjusted by the affixing member that is inserted through at least the one adjustment hole.</p>
