A belt driven continuously variable transmission unit which converts the rotation of the input member by continuously variable ratios, and a gear unit such as a planetary gear unit to which the output torque from said continuously variable transmission unit and torque from said input member transmitted through a transfer unit is fed and delivered to the output member, are provided. A clutch and arresting member, such as a brake and one-way clutch are provided on the input path to said gear unit from said transfer unit. When the arresting member is actuated to low speed mode, the gear unit functions as a reduction mechanism, whereas when the arresting member is engaged to high speed mode, the gear unit functions as a split-drive mechanism which combines the output torque from said continuously variable transmission unit with the torque transmitted through said transfer unit. Formation of torque loop is prevented while combining the torques, by driving the element of the gear unit which supports reaction when the gear unit is functioning as a reduction mechanism.