Abstract: A headlamp for an automobile includes a reflector, a filament, and a front lens, and the filament is disposed along the principal optical axis of the reflector. The basic surface of the reflecting surface has a shape obtained by adding deformations to an elliptical paraboloid which has an elliptical cross section at a plane perpendicular to the principal optical axis. The focal length of a cross section (parabola) of a basic surface in a horizontal plane including the principal optical axis is set to be smaller than the focal length of a cross section (parabola) of the basic surface in a vertical plane including the principal optical axis. A twist is added to a region of the reflecting surface located in close proximity to the horizontal plane including the principal optical axis, and upper edges of the projected filament images of the filament due to that region are aligned, thereby forming a line constituting a basis of a horizontal cutline.