The power transmission apparatus may include a control device to carry out idling stop control in such a manner that, when it is detected that an operating means is not operated for a predetermined time or more, an engine is stopped, and a clutch is disconnected, and the supply of the electric power from a battery to a motor generator is interrupted, and when it is detected that the operating means is operated afterwards, the engine is started by a cell motor, and the supply of the electric power from the battery to the motor generator is permitted, and the clutch is connected after the number of revolutions Ne of the engine reaches a predetermined value or more, and the supply of the electric power from the battery to the motor generator is interrupted.