To reduce the number of constituent parts on a planetary roller type power transmission device.

A planetary roller type power transmission device is constituted of bearing rings 19, 20 fixed on a housing constituted of a hollow housing main part 1 consisting of an end wall 1a and a peripheral wall 1b on one end side and the other end side of which is opened and a cover wall part 3 pressurized and fixed toward the housing main part 1 in such a way as to block by being engaged with an opening end of the housing main body 1, solar rollers 7, 8, carriers 11, 12 furnished with revolving pins 13, 14 and planetary rollers 16, 17 supported on the revolving pins through a pair of rolling bearings, making inexternally contact with the bearing rings and making, externally contact with the solar rollers 7, 8. Outer rings 15a of a pair of the rolling bearings are loosely fit on inner peripheral surfaces of the planetary rollers 16, 17, inner rings 15b are press fit and fixed on the revolving pins 13, 14, and the bearing rings fit and inserted on an inner peripheral surface of the housing main part are positioned in the axial direction as they are sandwiched and pressurized between the end wall and the cover wall part of the housing main body as the cover wall part is pressurized and fixed on the housing main body and fixed in the rotating direction.