To provide a bearing device of an idle gear in an engine output gearwheel train of an engine capable of elongating a durable life by reducing abrasion of a bearing, even when a torque on a driven wheel side of the output gearwheel train of the engine is increased and a load applied to the bearing of the idle gear is increased.

Idle gears 8A, 8B are rotatably and unmovably in an axial direction journaled around a shaft of a spindle 10 projected to a front wall 2A of a cylinder block 2 of an engine 1 via a ball bearing 11. Lubricating oil is supplied to the ball bearing 11 through an oil path 12 constituted of a first upstream oil path 12A and a second downstream oil path 12B.