A vehicular lamp includes a lamp outer case formed by a cover and a lamp housing; a light source disposed inside the lamp outer case; and a light guide that guides light emitted from the light source, wherein the light guide is shaped as a column. The light guide includes a first extension portion that extends on a horizontal plane side, and a second extension portion that extends on a vertical plane side with respect to a reference line that extends in a direction inclined 45 degrees with respect to the horizontal plane. An outer surface of the light guide includes an incident surface to which light emitted from the light source is incident, an internal reflection surface that internally reflects light incident from the incident surface, and a radiation surface that is formed as an outward-convexly curved surface and radiates at least light reflected by the internal reflection surface. ρ1 is a curvature of the radiation surface in a cross section perpendicular to a direction in which the first extension portion extends, ρ2 is a curvature of the radiation surface in a cross section perpendicular to a direction in which the second extension portion extends, and ρ1 is smaller than ρ2.