An actuating device for a heating element valve has a drive motor with a motor shaft, an actuator, and a rotation-linear conversion drive. The conversion drive is coupled on the drive side to the motor shaft and on the output side to the actuator and converts a rotational movement of the motor shaft into a linear movement of the actuator. The rotation-linear conversion drive further has a cam disc on the output side which is provided on its outer circumferential periphery with a plurality of step segments each having a substantially constant distance from the axis of the cam disc. The step segments are connected via connecting segments with a variable axle spacing.