Control apparatus for vehicle lamp and vehicle lamp system

A control apparatus (100) for a vehicle lamp (10) includes a receiver (102) to receive an acceleration signal indicative of an acceleration detected by an acceleration sensor (110), and a controller (104) to derive an inclination angle (¸) of a vehicle (300) relative to a horizontal plane from the acceleration signal. While the vehicle is stopped and if a change in the acceleration exceeds a threshold, the controller (104) outputs an adjustment signal indicative of an instruction to adjust an optical axis (O) of the vehicle lamp (10) in accordance with a difference in the inclination angle (¸) before and after the change in the acceleration.