The invention relates to the field of GIS devices, and in particular to an integratedly arranged isolating/earthing switch and an operation mechanism and transmission structure thereof. The integratedly arranged isolating/earthing switch includes an operation mechanism which includes a transmission structure and a drive apparatus. The transmission structure includes a worm and gear decelerator which has an input shaft and 2 output shafts. The input shaft and output shafts separately extend from 3 lateral sides of the worm and gear decelerator. The 2 output shafts are in respective transmission connection to an on/off indicator and an auxiliary switch. The on/off indicator and the auxiliary switch are arranged on the worm and gear decelerator, specifically on the lateral side which is parallel to the axes of the output shafts. According to the invention, the worm and gear decelerator of one core transmission mechanism is adopted to replace transmission structures that are scattered at each part of a machine frame of an original operation mechanism, the on/off indicator and the auxiliary switch are arranged in the periphery of the worm and gear decelerator, and integrate arrangement of the transmission mechanism is achieved and the volume of the entire apparatus is reduced.