A vehicular lamp including a light-emitting element 10 that emits light at
a greater diffusion angle in the lateral direction than in the vertical
direction, thus enabling the light to be incident on the rear face 34a of
a horizontally elongated inner lens 34 with high efficiency. The rear
face 34a has a cylindrical surface that extends in the lateral direction,
and the curvature of a convex curve, which forms the cross-sectional
shape of the cylindrical surface taken along the vertical plane parallel
to the optical axis Ax, gradually reduces according to the increase in
the distance from the optical axis Ax in the lateral direction, thus
allowing the curvature of the convex curve to be maintained at a
substantially constant value in the lateral direction and further
preventing the diffusion angle of the light into the lens in the vertical
direction from increasing in the lateral direction.