An improved lens unit can be used in an in-vehicle camera or the like, in a condition where a forefront lens is exposed to the outside for a long time. Here, the resin lens within the lens unit has an improved durability at a high temperature. The lens unit has a plurality of lenses arranged side by side with the optical axes thereof aligned with each other. The lenses include glass lens and resin lens. The lens closest to the object is a glass lens which is closest to the object side and is coated with an ultra-hard film. Resin lenses each have a high temperature resistant reflection preventing film. The lens is a combined lens in which a lens and a lens are bonded together, and is then covered with a high temperature resistant reflection preventing film after bonding.