To make improvements in the productivity of a planetary roller type power transmission device.

In this planetary roller type power transmission device, a planetary roller 9 to be circumscril:ed with a sun roller 5 and inscribed with a race 7 is supported on a driving pin 8 installed in the same circular set-up of a carrier part 6 free of rotation via a shell type needle roller bearing 10. At that time, a needle roller is inscrived with an inner circumferential source of a shell of this shell type needle roller bearing 10, and is circumscribed with an outer circumferential surface of the driving pin 8. A pin hole of the planetary roller is merely enough of accuracy for pressfitting the shell type needle roller bearing 10, namely, the shell alone, and a needle roller train comes to an assembly of tripartite integral by the shell and a retainer of the shell type needle roller bearing and it is insertable into the pin hole of the planetary roller.