To eliminate inconvenience in which noise and vibration are generated caused by drive-connection of a sun roller as an input shaft and a transmission shaft, in a planetary roller-type transmission.

In the planetary-roller type transmission, a sun roller 31 is formed into a cylindrical shape, and a cylindrical elastic member 30 is provided on the inner peripheral surface 31a. A circumferential surface 30d and a flat surface 30c as a flat part are provided on the inner peripheral surface 30a of the elastic member 30. The flat surface 30c is formed so as to intersect the circumferential direction. The outer peripheral surface 20a of a rotary shaft 20 of a motor 2 is fitted to the inner peripheral surface 30a of the elastic member 30, the flat surface 20c of the outer peripheral surface 20a and the flat surface 30c are brought into contact with each other, engaged with each other, and drive-connected to each other so as to transmit torque. Large torque transmitting capabilities can be reliably obtained by the flat surface without slipping. Therefore, assembly is facilitated, and assembling costs, costs of parts and maintenance costs can be reduced.