A control device for controlling a vehicle lamp provided in a vehicle, the device comprising: a receiver configured to receive an acceleration signal representing an acceleration of the vehicle, from a three-axis acceleration sensor configured to detect the acceleration of the vehicle, wherein an inclination angle (θ) of the vehicle with respect to a horizontal plane is calculated based on the acceleration signal; wherein the inclination angle (θ) comprises: a first angle (θr) that represents an inclination angle of the road surface with respect to the horizontal plane; and a second angle (θv) that represents an inclination angle of the vehicle with respect to the road surface, a controller configured to: i) generate a first control signal instructing the vehicle lamp to adjust an optical axis of the vehicle lamp in response to a change of the acceleration signal, during a stop of the vehicle; and ii) generate a second signal instructing the vehicle lamp to maintain the optical axis of the vehicle lamp, when the vehicle is traveling on a road surface; characterized in that the controller is configured to save the first angle as a first reference value and the second angleas a second reference value, if the change in the acceleration is greater than a threshold value during the stop of the vehicle, the controller calculates a new second reference value based on the first reference value and the inclination angle, saves the new second reference value and generates the first control signal using the new second reference value, and when the vehicle has stopped after traveling on a road surface, at a time where a detected value of the acceleration sensor is stable, the controller calculates a new first reference value based on the second reference value and the inclination angle and saves the new first reference value. a receiver configured to receive an acceleration signal representing an acceleration of the vehicle, from a three-axis acceleration sensor configured to detect the acceleration of the vehicle, wherein an inclination angle (θ) of the vehicle with respect to a horizontal plane is calculated based on the acceleration signal; wherein the inclination angle (θ) comprises: a first angle (θr) that represents an inclination angle of the road surface with respect to the horizontal plane; and a second angle (θv) that represents an inclination angle of the vehicle with respect to the road surface, a controller configured to: i) generate a first control signal instructing the vehicle lamp to adjust an optical axis of the vehicle lamp in response to a change of the acceleration signal, during a stop of the vehicle; and ii) generate a second signal instructing the vehicle lamp to maintain the optical axis of the vehicle lamp, when the vehicle is traveling on a road surface; characterized in that the controller is configured to save the first angle as a first reference value and the second angleas a second reference value, if the change in the acceleration is greater than a threshold value during the stop of the vehicle, the controller calculates a new second reference value based on the first reference value and the inclination angle, saves the new second reference value and generates the first control signal using the new second reference value, and when the vehicle has stopped after traveling on a road surface, at a time where a detected value of the acceleration sensor is stable, the controller calculates a new first reference value based on the second reference value and the inclination angle and saves the new first reference value. a first angle (θr) that represents an inclination angle of the road surface with respect to the horizontal plane; and a second angle (θv) that represents an inclination angle of the vehicle with respect to the road surface, a controller configured to: i) generate a first control signal instructing the vehicle lamp to adjust an optical axis of the vehicle lamp in response to a change of the acceleration signal, during a stop of the vehicle; and ii) generate a second signal instructing the vehicle lamp to maintain the optical axis of the vehicle lamp, when the vehicle is traveling on a road surface; i) generate a first control signal instructing the vehicle lamp to adjust an optical axis of the vehicle lamp in response to a change of the acceleration signal, during a stop of the vehicle; and ii) generate a second signal instructing the vehicle lamp to maintain the optical axis of the vehicle lamp, when the vehicle is traveling on a road surface; characterized in that the controller is configured to save the first angle as a first reference value and the second angleas a second reference value, if the change in the acceleration is greater than a threshold value during the stop of the vehicle, the controller calculates a new second reference value based on the first reference value and the inclination angle, saves the new second reference value and generates the first control signal using the new second reference value, and when the vehicle has stopped after traveling on a road surface, at a time where a detected value of the acceleration sensor is stable, the controller calculates a new first reference value based on the second reference value and the inclination angle and saves the new first reference value.