A parallel axes type automatic transmission including a first input shaft having m or more (m is an integer not less than 2) wet multiplate clutches and drive gears rotatably mounted, a second input shaft having n or more (n is an integer greater than m and not less than 3) wet multiplate clutches and drive gears rotatably mounted, and a third input shaft having m or less wet multiplate clutches and drive gears rotatably mounted. The automatic transmission further includes an output shaft having a fixed final drive gear and a plurality of fixed driven gears. The first, second, and third input shafts are arranged at different levels so that the second input shaft is arranged at the highest level, the first input shaft is arranged at the middle level, and the third input shaft is arranged at the lowest level.