Engine starting method in idling stop condition

The present invention provides an engine starting method from an idling stop condition wherein a preliminary step pushes a pinion (110) to abut with a ring gear (10) when a vehicle operating condition is in an idling stop condition, a starting step rotates the pinion (110) into mesh with the ring gear (10) by a motor (2) upon receiving an engine start signal and thereafter an engine is started, and a restoring step is carried out after engine startup where the pinion (110) is restored to an original position thereof. Also provided, when the engine is stopped, a pinion (110) is meshed with a ring gear (10). Upon engine start-up, a pinion (110) actuator disengages the pinion (110) from the ring gear (10) and a cutout portion engages an engaging piece to maintain the pinion (110) disengaged. When the engine stops, a releasing actuator disengages the cutout portion and the engaging piece and the pinion (110) is reset.