An imaging unit has an imaging device that has an imaging lens; a case that encloses an imaging device and that has an imaging portion for passing light that is to be incident into an imaging lens; and an extending portion that extends from the opening portion in the imaging direction of the imaging device. The extending portion has an extending surface that is provided with a scattering portion for scattering light through structural units. Each structural unit has a surface structure for reflecting, in at least two mutually differing directions that are inclined in relation to a first vertical plane, light that is inclined in the imaging direction relative to an axis that is perpendicular to the extending surface, and that is parallel to a first vertical plane that is perpendicular to the extending surface and that includes the optical axis of the imaging lens.