A vehicular automatic transmission, includes: a housing; input and output shafts sustained to be rotatable around a rotation shaft line in the housing; single pinion type first, second and third planetary gears sustained in parallel coaxially with the rotation shaft line; a first brake fixing a third ring gear of the third planetary gear to be disengageable with respect to the housing; a first clutch linking the third ring gear and a second carrier of the second planetary gear to be disengageable from each other; and a switching element blocking the link between the input shaft and the first carrier, and switching the input shaft to be in a switched state, wherein, in a reverse gear shift stage, the first clutch is in an engaged state, the first brake is in a fixed state, and the switching element is in a switched state.