A planetary gear mechanism (17) distributes the rotation of a carrier (17c) which is coupled to an input shaft (3) to a sun gear (17a) and a ring gear (17d). A toroidal variator (22) and a first power transmission mechanism (10) transmit the rotation between the sun gear (17a) and a countershaft (20). A second power transmission mechanism (9) transmits the rotation of the ring gear (17d) to the countershaft (20). A ratio α 1 of the number of teeth of the sun gear (17a) and ring gear (17d) is set so as not to fall below a reduction ratio R1 of the first power transmission mechanism (10) and a reduction ratio R2 of the second power transmission mechanism (9) so as to prevent slippage of power rollers (8) in the toroidal variator (22).