In an eccentric-drive equipped seat reclining device including a cover having internal teeth, a base member, an external gear having fewer external teeth than a number of the internal teeth, a pair of wedge-shaped members and a guide plate located in an eccentric space between the cover and the external gear, a spring biasing the pair of wedge-shaped members apart from each other, and a driving member for circumferentially pushing the pair of wedge-shaped members, the external gear has a cylindrical protrusion. The base member has a first axially-recessed portion for press-fitting the external gear to the base member, a second axially-recessed portion accommodating the cylindrical protrusion, and a third axially-recessed portion accommodating the spring. Protrusions, formed integral with an annular outer peripheral portion of a backface of the second axially-recessed portion, are fitted to respective recessed portions of a seat-cushion side arm.