For producing a toroidal disc for a traction drive device, the following steps are employed. First, a circular steel body is prepared which has been subjected to a carbonitriding hardening/tempering process. The steel body has a concentric toroidal surface which is formed with a plurality of fine recesses each having a depth of smaller than 3 nullm. Then, the circular steel body is turned about a rotation axis thereof. Then, a ball member is pressed against the toroidal surface with a given pressing force. And then, the ball member is moved on a given angular range of the toroidal surface in a direction perpendicular to the rotation axis of the circular steel body while being pressed against the toroidal surface with the given pressing force.