An electric power steering device includes a worm which is swingably connected to the rotation shaft of an electric motor through a joint. A first end portion and second end portion of the worm are supported by a first bearing and a second bearing, respectively. A pair of elastic members elastically urge the worm to an axial neutral position. An annular leaf spring which is held by a housing urges the second end portion toward a worm wheel through the second bearing. A synthetic resin member having a sliding contact surface which is in contact with the leaf spring is integrally disposed on the second bearing.