An automatic transmission capable of improving stability and reliability of connection operation of a synchronization mechanism when pre-shift control is executed, thereby making it possible to prolong the service life of the mechanism and improve marketability thereof. To change the speed position of a vehicle, one of two power transmission paths from an internal combustion engine to drive wheels is switched to the other, and pre-shift control is executed before switching the path. In doing this, when conditions for executing the pre-shift control are satisfied, whether or not a motive power fluctuation state of the engine occurs after satisfaction of the execution conditions is determined. If the motive power fluctuation state occurs, delay control for delaying the start of the pre-shift control is executed, whereas if the same does not occur, the pre-shift control is executed without executing the delay control.