The invention provides a flexible transmission device applicable to a 27.5kV switch cabinet interior isolating switch. The device is mounted within a mechanism chamber of an operating mechanism for an isolating switch cabinet. A separating transmission wheel disk of the transmission device for separating the flexible wire transmission device is connected fixedly with a main shaft of the isolating switch; a guide sleeve fixing plate and a drawn wire guide sleeve are fixed to each other by threads. The steel wire sleeve in the flexible steel drawn wire is wound on the separating transmission wheel disk. The mechanism flexible wire driving wheel disk of the mechanism flexible wire driving device is fixed together with a drive main shaft of the operating mechanism by a bolt. The guide sleeve fixing plate and the drawn wire guide sleeve are mounted on the bottom plate bracket or the sidewall of the mechanism chamber of the operating mechanism after being connected fixedly with each other by threads; the steel wire sleeve in the flexible steel drawn wire is wound on the mechanism flexible driving wheel disk. The flexible transmission device provided by the invention has the effects that the relative position relationship necessarily kept for the isolating switch and the operating mechanism is not needed to be considered for the transmission device; the reliability of the primary high pressure system scheme arrangement of the isolating switch in the field within a switch cabinet is improved.