An automatic transmission includes a first planetary gear set; a second planetary gear set; a third planetary gear set; an input shaft; an output shaft; and five friction elements. A first ring gear is constantly locked. A third carrier is connected with a second ring gear to define a rotating member. The input shaft is constantly connected with a second carrier, and the output shaft is constantly connected with the rotating member. The five friction elements are adapted to selectively connect among the carriers, ring gears and sun gears. Each of at least seven forward speed-ratios and one reverse speed-ratio is achieved by an engaged state of two friction elements selected from the five friction elements.