Lens unit and manufacturing method of lens unit

A lens unit comprising:

• a lens element provided with a convex surface on at least one of an incident surface and an exit surface of the lens element, the lens element having a positive refractive power that condenses light rays, emitting from a light source, at a predetermined position;
• and
• a lens frame that supports the lens element within the lens frame, the lens frame provided with a projection that projects in an inner radial direction from an inner portion of the lens frame,
• wherein the lens frame supports the lens element with the projection fixedly fitted into an outer peripheral portion of the lens element,
• wherein the projection is provided, on an inner peripheral portion thereof, with a first surface positioned on an incident side in an optical axis direction of the lens element, a second surface positioned on an exit side in the optical axis direction, and a third surface positioned between the first surface and the second surface, and
• wherein the first, second and third surfaces are tapered surfaces that are respectively obliquely inclined relative to the optical axis direction and progressively vary the inner diameter of the lens frame in the optical axis direction.