a mounting structure for mounting a steer - by - wire vehicle steering apparatus on a vehicle body side , comprising : a housing for rotatably retaining therein one end of a steering shaft of the steering apparatus , while retaining therein an actuator for exerting reactive force in order to impart reactive force in response to turning of an operating member fastened to an other end of the steering shaft that projects from the housing and rotatable together with the steering shaft ; and a plurality of mounting portions disposed about a turning axis of the operating member so as to extend diametrically outwardly , the mounting portions fastened at respective fastener portions thereof to a vehicle body side at multiple locations , at least one of the fastener portions of the mounting portions is fastened to the body side via a rubber elastic body so that the housing is elastically supported on the body side .