An automatic transmission including a Ravigneaux planetary gear unit, an input member, an output member disposed on one side of the Ravigneaux planetary gear unit, five friction elements disposed on the other side of the Ravigneaux planetary gear unit, and a partition member cooperating with an automatic transmission case to define a transmission chamber in which the output member, the Ravigneaux planetary gear unit, and the respective friction elements are accommodated. The output member is supported on a cylindrical portion extending from the partition member toward the Ravigneaux planetary gear unit in an axial direction of the input member.