Abstract: A headlamp for a motor vehicle with a linear bubble tube type level vial 60 for detecting a vertical inclination of a vial 60 in which the reflector 14 is supported so as to be tiltable with respect to a lamp body 10 within a lamp chamber S defined by the lamp body 10 and a front lens 12, and the vial 60 contains a linear bubble tube 64 substantially horizontally and longitudinally disposed, characterized in that the level vial 60 is extended rearward from the rear wall of the reflector 14, whereby the level vial 60 is located apart from a heat source (bulb 16), thereby impeding the transfer of the heat to the linear bubble tube 64 of the level vial 60. A rear expanded portion 11 enclosing the level vial 60 is additionally formed to the lamp body 10, without increasing the size of the whole lamp body 10 in connection with the level vial 60. With this unique structure, the increase of the size of the lamp body 10 is not so much.