Abstract: Disclosed is a centrifugal spark-advance control device for an ignition system of an internal combustion engine, comprising: a base plate which rotates at a speed corresponding to the rotational speed of the engine; a timing plate which is rotatably supported on the base plate; a spring for biasing the timing plate in a certain direction; a centrifugal weight which is pivoted to the base plate at a point spaced from the center of gravity of the centrifugal weight and which is provided with a cam surface for rotatably driving the timing plate in an opposite direction against the biasing force of the spring by cooperating with a corresponding cam follower surface provided in the timing plate; a spark generating device coupled to the timing plate for generating ignition sparks in synchronism with the rotational angle of the timing plate; a mass member attached to the timing plate by way of an elastic member.