To feed the lubricating oil to each parts of an input shaft and an output shaft sufficiently, in a transmission with transfer of an input/output shaft concentric type.

An input shaft 6 and an output shaft 7 are provided concentrically, and an auxiliary shaft 8 and a front wheel output shaft 9 are provided parallel to both shafts 6 and 7. The end of the input shaft 6 is inserted rotatable relatively to the recess of the output shaft 7 through a bearing 19. Lubricating oil passages 52 and 58 are provided in the input shaft 6 and the output shaft 7 respectively. One end of a pipe 62 is inserted to the lubricating oil passage 52 on the input shaft 6 side, while the other end of the pipe 62 is inserted to the lubricating oil passage 58 on the output shaft 7 side by keeping a clearance. The lubricating oil sprung up by rotating a large diameter of reduction gear on the input shaft 6 side is led in to the lubricating oil passage 52 through an oil chamber 54, and furthermore, it is led in to the lubricating oil passage 58 on the output shaft 7 side through the pipe 62. By the centrifugal force by rotating the input shaft 6 and the output shaft 7, a sufficient lubricating oil can be fed to the parts of the input shaft 6 and the output shaft 7.