An automatic transmission includes a first single-pinion planetary gear mechanism including a first sun gear, a first ring gear, and a first carrier that respectively correspond to first to third elements in a velocity diagram. A second single-pinion planetary gear mechanism includes a second sun gear, a second ring gear, and a second carrier that respectively correspond to fourth to sixth elements in a velocity diagram. The fourth element is connected to the first element to form a first connected body. A double-pinion third planetary gear mechanism includes a third sun gear, a third ring gear, and a third carrier that respectively correspond to seventh to ninth elements in a velocity diagram. The ninth element is connected to the third element to form a second connected body. The eighth element is connected to the fifth element to form a third connected body.