Abstract: A sliding rail structure for use in cuckoo clocks comprises a base including a guiding member provided thereon and having an elongated sliding piece correspondingly fixed thereon, the sliding piece including a rack mounted on one side thereof, and including an engaging recess formed on the front end thereof for inserting a stem of a cuckoo element, characterized in a casing and a housing are fixed onto the base for pressing against the two sides of the sliding piece, respectively, thus obtaining a stable reciprocating movement of the sliding piece, and the guiding member further includes an elongated slot formed at the center thereof, a peg is extendedly arranged on the bottom of the sliding piece for being fitted into the guide slot of the guiding member, and for screwing a confining element therein, thereby preventing the disengagement of said sliding piece for causing a stopping effect.