A traction-drive force transmission mechanism, includes a sun roller rotatable about a first axis and a plurality of shafts. Each is disposed on an adjacent axis inclined relative to the first axis. Planetary rollers are disposed along an outer peripheral surface of the sun roller and are supported respectively by the shaft. A carrier holds each of the shafts in the inclined posture and is adapted to be rotated about the first axis together with the planetary rollers. A pressing member pressingly moves each planetary roller in a direction for reducing a distance to the first axis so as to press each planetary roller against the outer peripheral surface of the sun roller. Thus a driving force can be transmitted to a traction force between the sun roller and each of the planetary rollers.