PURPOSE: To provide a simple and sure advancer with good responsiveness by supporting rollers which vary a fuel injection timing by means of a roller holder, detecting a real advance quantity so as to feedback it and controlling a motor so as to vary the advance quantity of the roller holder in respone to an exiting operational condition.

CONSTITUTION: The same number of rollers 20 of cylinders in a diesel engine are supported by a roller holder 19, and a pheripheral face gear 44 is formed on the outer pheripheral face. A motor 46 is provided as a motor for varying advance ange so as to engage its pinion gear 45 with the pheripheral face gear 44. A real advance quantity of the roller holder 19 is detected by a potentiometer 47, and inputed in a controller (ECU). Information such as engine rotational speed, water temperature, etc., are inputted in the controller, and rotational control of the motor 46 for varying the advance angle is performed, and thereby roller holder 19 is rotated. Consequently, an advancer which is automatically and surely opereated in the simple constitution, and prtided with good responsiveness can be thus obtained.