In a headlamp comprising low beam irradiating, there are provided main beam
irradiating means, light distribution switching means for switching a low
beam and a main beam, abnormality detecting means for detecting an
abnormal situation in which a proper low beam cannot be formed, and
optical axis tilting means for vertically tilting an optical axis of at
least a main beam, and the abnormality detecting means detects an
abnormality, a light distribution is switched into a main beam by the
light distribution switching and the optical axis of the main beam is
turned downward by the optical axis tilting means. When a proper low beam
cannot be formed, a main beam having a larger light amount is generally
turned on to maintain a visibility in of a vehicle and the optical axis of
the main beam is turned downward such that glare light is not generated.
