A vehicular light guiding body comprising: an incidence surface on which light from a light source is incident; a first reflection surface that internally reflects the light incident from the incidence surface and converts the light into substantially parallel light; a second reflection surface that has a shape based on a paraboloid of revolution in a cross-section in a vertical direction in an onboard state in which a vehicular headlight is mounted on a vehicle and, which reflects the substantially parallel light from the first reflection surface toward a focus point; a light blocking part that blocks a portion of the light reflected by the second reflection surface; and an emission surface that emits the light internally reflected by the second reflection surface to pass through the light blocking part, and projects a headlight pattern toward a front of a vehicle, wherein a plurality of the incidence surfaces (21, 21M, 21N) are provided, and the first reflection surface and the second reflection surface are provided so as to correspond to each of the incidence surfaces (21, 21M, 21N), wherein a plurality of the second reflection surfaces (23, 23M, 23N) are provided, and the plurality of the second reflection surfaces (23, 23M, 23N) include both a condensing pattern forming surface that internally reflects the substantially parallel light such that the substantially parallel light passes through the focus point and the vicinity of the focus point, and a diffusion pattern forming surface that internally reflects the substantially parallel light such that the substantially parallel light passes through a position shifted to an outer side in a horizontal direction in an onboard state with respect to the focus point including the focus point. an incidence surface on which light from a light source is incident; a first reflection surface that internally reflects the light incident from the incidence surface and converts the light into substantially parallel light; a second reflection surface that has a shape based on a paraboloid of revolution in a cross-section in a vertical direction in an onboard state in which a vehicular headlight is mounted on a vehicle and, which reflects the substantially parallel light from the first reflection surface toward a focus point; a light blocking part that blocks a portion of the light reflected by the second reflection surface; and an emission surface that emits the light internally reflected by the second reflection surface to pass through the light blocking part, and projects a headlight pattern toward a front of a vehicle, wherein a plurality of the incidence surfaces (21, 21M, 21N) are provided, and the first reflection surface and the second reflection surface are provided so as to correspond to each of the incidence surfaces (21, 21M, 21N), wherein a plurality of the second reflection surfaces (23, 23M, 23N) are provided, and the plurality of the second reflection surfaces (23, 23M, 23N) include both a condensing pattern forming surface that internally reflects the substantially parallel light such that the substantially parallel light passes through the focus point and the vicinity of the focus point, and a diffusion pattern forming surface that internally reflects the substantially parallel light such that the substantially parallel light passes through a position shifted to an outer side in a horizontal direction in an onboard state with respect to the focus point including the focus point.