AUTOMOTIVE LAMP

A scanning light source includes a semiconductor light source and a motor, and scans output light of the semiconductor light source in front of a lamp according to the movement of the motor. A constant current driver supplies a driving current Ito the semiconductor light source according to a light source control signal. A light source control signal generator generates the light source control signal so as to obtain a light distribution pattern that corresponds to light distribution instruction data. A delay time measurement device measures the delay time required for the transition of the on/off states of the semiconductor light source from the change of the light source control signal.