Roller (1), particularly a castor-type roller, with rotational movement of a running wheel (12), with an operating shaft (20) which passes through a control cam (19) of the roller (1) and on which an electric motor (37) acts via a gear mechanism to operate it, wherein the electric motor (37) acts on the operating shaft (20) by means of an electric motor shaft (39) via a toothed gear mechanism (38), the toothed gear mechanism (38) having a driven gear wheel (41), a hub (40) of which is passed through by the operating shaft (20).