A vehicle status judging unit determines whether the following conditions are met: the shift position of a shift lever 4 is the F or R position (condition 1); brakes (5, 6, 8) are inactive (condition 2); the vehicle stands still (condition 3); the depressed amount of an accelerator pedal 9 is equal to or less than ´ (condition 4); and the rotational speed of an engine 1 is equal to or less than a medium rotational speed (condition 5). An engine rotation control unit controls the engine 1 such that the rotational speed of the engine 1 become equal to a minimum rotational speed if conditions 1, 2, and 4 are met and condition 3 is not met or if condition 1 is met and condition 2 is not met. The engine rotation control unit also controls the engine 1 such that the rotational speed of the engine 1 becomes equal to the medium rotational speed if conditions 1, 2, 3, and 5 are met or if conditions 1, 2, and 5 are met and conditions 3 and 4 are not met.
