Provided is an automotive lamp assembly that can dynamically control the amount and direction of side radiation of light, as a vehicle travels along a curved road. The lamp assembly includes a projection lamp module including a light source, a reflecting mirror reflecting light emitted from the light source forward, and a lens refracting and condensing the forward reflected light; a rotative actuator rotating the module about a predetermined driving axis; and an additional reflecting mirror rotating with the module and reflecting light intercepted by a shield to make the light travel at an angle in a direction proportionate to the rotation.