To provide a rotation braking device capable of being miniaturized, which is easily attachable to a joint part of a joint link mechanism, and which can be securely locked by applying a brake to a rotation part.

The rotation braking device has a brake intermediate ring 9 for applying a pressing force which becomes a braking force to an annular brake plate part 61 of a brake ring main body 6 which is fitted so as to stop rotation and move in the axial direction inside the case 1. To the edge of the case 1, a brake outer ring 2 rotated by a rotary actuator 16 is rotatably fitted. On a face opposite the brake outer ring 2 and the brake intermediate ring 9, a first annular inclined face 22 and a second annular inclined face 91 are formed, each having a plurality of arcuate inclined faces arranged in a circle via step parts. A roller assembly body 3 is arranged so as to sandwich a plurality of rollers 4 from both sides, comprising the rollers 4 rotatably supported inside an arcuate retainer, between the first annular inclined face 22 and the second annular inclined face 91.