A clamping mechanism for clamping an industrial input/output device on a DIN rail, comprising: a shell member , comprising a mechanism assembly receiving space formed at a rear side thereof, a first clamping rod disposed in the mechanism assembly receiving space, and comprising a first driving part , an elastic element mounting part , a first clamping part and a second driving part , and a part of the first clamping part is exposed out of the shell member ; an elastic element secured in the mechanism assembly receiving space through the elastic element mounting part ; a rotary rod pivotally disposed in the mechanism assembly receiving space, and comprising a first rotary driving part and a second rotary driving part , wherein the second driving part is assembled with the first rotary driving part ; and a second clamping rod disposed in the mechanism assembly receiving space, and comprising a third driving part and a second clamping part , wherein the third driving part is assembled with the second rotary driving part , and a part of the second clamping part is exposed out of the shell member , characterized in that the shell member further comprises a sliding track disposed at a top side thereof, the sliding track comprising a first sliding track end and a second sliding track end ; an operating link comprising a pivot pin , a rod sliding slot , a first operating part and a second operating part , and slidably and rotatably disposed on the sliding track through the pivot pin , wherein the first operating part and the second operating part are exposed out of the shell member , and the rod sliding slot comprises a first sliding slot end and a second sliding slot end ; wherein the first driving part of the first clamping rod is disposed in the rod sliding slot and slidable relative to the rod sliding slot . a shell member , comprising a mechanism assembly receiving space formed at a rear side thereof, a first clamping rod disposed in the mechanism assembly receiving space, and comprising a first driving part , an elastic element mounting part , a first clamping part and a second driving part , and a part of the first clamping part is exposed out of the shell member ; an elastic element secured in the mechanism assembly receiving space through the elastic element mounting part ; a rotary rod pivotally disposed in the mechanism assembly receiving space, and comprising a first rotary driving part and a second rotary driving part , wherein the second driving part is assembled with the first rotary driving part ; and a second clamping rod disposed in the mechanism assembly receiving space, and comprising a third driving part and a second clamping part , wherein the third driving part is assembled with the second rotary driving part , and a part of the second clamping part is exposed out of the shell member , characterized in that the shell member further comprises a sliding track disposed at a top side thereof, the sliding track comprising a first sliding track end and a second sliding track end ; an operating link comprising a pivot pin , a rod sliding slot , a first operating part and a second operating part , and slidably and rotatably disposed on the sliding track through the pivot pin , wherein the first operating part and the second operating part are exposed out of the shell member , and the rod sliding slot comprises a first sliding slot end and a second sliding slot end ; wherein the first driving part of the first clamping rod is disposed in the rod sliding slot and slidable relative to the rod sliding slot . <EOS>