switching device phsd shown in fig3 in fig4 a case 2 is mounted on top of a tank 1 for enclosing an operating mechanism as described hereinafter covers 3a and 3b are mounted to conducting members 5a and 5b through insulating members 4a and 4b opening projecting portions are provided in the under portion of the tank 1 to facilitate mounting the conducting members 5a and 5b have a stationary contact fixed thereon which is coupled to the bus bars a and b shown in fig3 an insulating spacer 7 having a connector 8 connected to the gas circuit breaker gcb is mounted on a side wall of the tank 1 a shaft 9 fixed on a pinion 10 of a rack and pinion mechanism is supported by the case 2 so as to rotate freely a pair of movable racks 11a and 11b which are free to move up and down and which hold the pinion 10 therebetween are provided at both sides of the pinion 10 so as to move oppositely with respect to each other by rotating the pinion 10 a pair of series bodies consisting integrally of insulating rods 12a and 12b and movable contacts 13a and 13b to be engaged to the stationary contacts 6a and 6b are respectively rigidly mounted on one side of the respective racks 11a and 11b intermediate contactors 14a and 14b are electrically connected to the connector 8 and slidingly contact movable contacts 13a and 13b the stationary contact 6a and movable contact 13a constitute disconnecting switch ds 2 the stationary contact 6b and the movable contact 13b constitute the disconnecting switch ds 1 the operation.