AUTOMATIC TRANSMISSION

PROBLEM TO BE SOLVED: To achieve multistage transmission by a fewer number of planetary gear mechanisms in an automatic transmission that shifts gears on the power input to an input member to output the power to an output member.SOLUTION: The automatic transmission includes: a double-pinion type planetary gear mechanism 30 having a sun gear 32, a ring gear 34 and a carrier 38; a single-pinion type planetary gear mechanism 40 having a sun gear 42, a ring gear 44 and a carrier 48; a single-pinion type planetary gear mechanism 50 having a sun gear 52, a ring gear 54 and carrier 58; clutches C1 to C5; and brakes B1 and B2. An input shaft 22 is connected to the sun gear 32; an output gear 24 is connected to the ring gear 44; and the ring gear 34 is connected to the ring gear 54. The clutch C1 is connected to an input shaft 22 and the carrier 48; the clutch C2 is connected to the carrier 48 and the carrier 58; the clutch C3 is connected to the ring gear 34 and the sun gear 42; the clutch C4 is connected to the carrier 38 and the sun gear 42; the clutch C5 is connected to the carrier 38 and the sun gear 52; the first brake B1 is connected to the carrier 58; and the second brake B2 is connected to the sun gear 52.