A twin-clutch transmission wherein a center distance between input shafts and an auxiliary speed-change shaft can be shortened and the number of gears can be reduced. A twin-clutch transmission is provided which includes a first input shaft and a second input shaft, an auxiliary speed-change shaft, and a plurality of gear pairs. The first and second input shaft are connected, through a first clutch and a second clutch, respectively, to an input element, and disposed on the same axis. The auxiliary speed-change shaft is disposed parallel to the first and second input shafts. The plurality of gear pairs are provided between the first and second input shafts and the auxiliary speed-change shaft. An input path from the input element to the first clutch is different from that to the second clutch, and primary ratios of the input paths are set to values, respectively, different from each other.