Abstract: In an infinite speed ratio transmission a fixed speed ratio transmission (130) outputting the rotation of a first shaft (310A, 310B) at a fixed speed ratio to a first gear (132) on a second shaft (320), and a continuously variable transmission (100) outputting the rotation of the first shaft (310A, 310B) at an arbitrary speed ratio to a second gear (142) fixed to the second shaft (320) are provided. Further, a planetary gear set (120) comprising a sun gear (120S), planet carrier (120C) and a ring gear (120R) is disposed between the first gear (132) and second gear (142), and a final output gear (3) is disposed between the planetary gear set (120) and second gear (142). The sun gear (120S) is joined to the second gear (142), the planet carrier (120C) is joined to the first gear (132) and the ring gear (120R) is joined to the final output gear (3). With this arrangement, the infinite speed ratio transmission can be made compact.