Abstract: An engine lubricating system includes a lubricating oil supply mechanism having a plunger member adapted to be reciprocated in the axial direction in response to an engine output shaft to discharge lubricating oil, a control pin which is adapted to abut against the plunger member and is movable to change the stroke of the plunger member, thereby changing the discharge rate of the plunger member, and an electric actuator which moves the control pin to change the stroke of the plunger member. The engine operating condition is detected by way of at least both the engine load and the engine speed, and an electrical control unit outputs an electric control signal for controlling the electric actuator to change the discharge rate according to the engine operating condition.