Abstract: A circuit for controlling a liquid crystal rear-vision mirror is disclosed. The liquid crystal rear-vision mirror is equipped in an automobile to sense the amount of lights incident upon the mirror itself from a headlight of another automobile following behind. When the level of incident lights goes higher than a pre-determined level, the circuit generates a pulse signal of a fixed period to make the liquid crystal shutter properly function so that the amount of said incident light reflecting from the mirror to the driver will be decreased to a level adequate to secure driving safety.