An automatic transmission includes two clutches that are disposed such
that they overlap in an axial direction and occupy different positions in
a radial direction. Each of the two clutches includes a clutch drum, a
piston that forms a working fluid chamber for which a portion of the
clutch drum serves as a cylinder, a plurality of friction plates that
engage the clutch drum, and a cancel oil chamber that is disposed on a
rear face side of the piston and that cancels a centrifugal oil pressure
that acts on the working fluid chamber.