PURPOSE: To provide an escalator-driven step chain device to be used for a curved escalator by providing an eccentric cam means to connect a pair of links in which the overlapping degree of the adjustable links when a step is moved through each of transition areas.

CONSTITUTION: Internal and external step chain devices which are continuously connected between step shafts and connect all steps over the whole traveling passage of an escalator are provided. In the transition area, a cam mechanism 35 which is operated to change the overlapping degree of adjustable links 25, 26 and connects adjustable link pairs 25, 26 at least to one of the internal and external step chains is provided when the steps are moved through each of the transition areas so that the outer side of the step shaft of adjacent steps is moved through in the approaching direction to each other and the separating direction from each other.