An automatic transmission has a clutch mechanism, an oil pump, and a valve body that encloses a clutch hydraulic pressure control mechanism. The valve body is arranged axially adjacent to the clutch mechanism. The oil pump is offset from an input shaft of the transmission and arranged so as to overlap the valve body and/or the clutch mechanism when viewed from a direction perpendicular to the axial direction of the automatic transmission. This automatic transmission improves the control response of the clutch of the transmission while avoiding an increase in the size of the transmission.