The gross output power of an engine distributed to at least one main machine and one auxiliary machine. A total load value calculation unit calculates the value of the lost power consumed by the auxiliary machine, and calculates the value of total load power by adding to this lost power value a target value for the main output power of the engine to be distributed to the main machine. A gross output value control unit controls the value of the gross output power so that the value of the gross output power becomes equal to the value of the total load power when the value of the total load power is less than a predetermined threshold value, and so that the value of the gross output power becomes equal to the above described threshold value when the value of the total load power is greater than the threshold value.