<p>An electric power steering system (1) is provided, which comprises a steering assist electric motor (15), and a reduction gear mechanism (17) for reducing a rotation speed of a rotatable shaft (16) of the electric motor (15). The reduction gear mechanism (17) comprises a worm shaft (18) driven by the rotatable shaft (16), and a worm wheel (19) driven by the worm shaft (18). The electric power steering system further comprises a joint (34) for coupling the rotatable shaft (16) to the worm shaft (18) for transmission of a driving force. Longitudinally biasing means (37) is provided in association with the joint (34) for longitudinally biasing the worm shaft (18). <IMAGE></p>
