An automatic transmission includes a starting apparatus having a housing that rotates based on torque of a driving source, and a clutch mechanism portion positioned in the housing; an oil pump that is positioned on a side opposite to the driving source with respect to the starting apparatus in a rotational axis direction of the housing, and is driven by transmission of rotation of the housing; an oil pump housing in which the oil pump is accommodated; and a speed change mechanism that is positioned on a side opposite to the starting apparatus with respect to the oil pump housing in the rotational axis direction, and has an input shaft, which extends through the oil pump and the oil pump housing and is connected to the clutch mechanism portion.