A vehicular lamp with an optical axis adjusting device includes a housing, a reflector assembly pivotably mounted to the housing, a light source assembly mounted to the reflector assembly, and the optical axis adjusting device mounted to the reflector assembly. The optical axis adjusting device includes a threaded shaft and a fulcrum. The fulcrum is pivotably mounted to the reflector assembly and threaded with the threaded shaft. When the threaded shaft is rotated, the fulcrum can move along the axial direction of the threaded shaft and drive the reflector assembly to pivot with respect to the housing, so the angle of the optical axis of the vehicular lamp can be adjusted.