Lens and license lamp

A lens that diffuses outgoing light emitted from a light source, the lens comprising:

• a diffuser that includes an incident surface and an emission surface, wherein the incident surface is a surface through which the outgoing light enters the lens, the incident surface being formed at a portion opposed to the light source;
• and wherein the emission surface is a surface through which incident light incident on the incident surface exits from the lens;
• a locking portion provided in an outer circumferential surface of the diffuser and is in a shape projecting outward from the outer circumferential surface of the diffuser;
• and
• a flange that is in a shape protruding outward from a tip end of the diffuser in a direction from the incident surface toward the emission surface, wherein
• the diffuser is formed between the locking portion and the flange,
• the incident surface refracts the outgoing light in a direction away from an optical axis of the outgoing light, along a direction orthogonal to the optical axis, and
• the emission surface refracts the incident light in a direction away from a centerline of the incident light, along a direction orthogonal to the centerline, wherein
• the incident surface includes a pair of end incident portions formed at opposing ends in an orthogonal direction orthogonal to a first direction of connection between the incident surface and the emission surface, and
• each of the pair of end incident portions extends in a second direction orthogonal to both the first direction and the orthogonal direction and is in a shape convexly curved inward in the orthogonal direction.