An automatic transmission is provided, which includes a variator having a first pulley, a second pulley and a belt wound around the first and second pulleys, a first motor configured to give a pulley thrust force for shifting the variator to the first or second pulley, a second motor configured to cause a belt clamping force to be generated in the variator, and a power transmission mechanism provided between the second motor and the variator, to transmit an output torque of the second motor to the variator. The power transmission mechanism includes a cycloid decelerator configured to decelerate an input torque from the second motor, and transmit the decelerated input torque to the variator.