PURPOSE: To enable deterioration in a conducting characteristic between a contact shoe on the sandwiching side and a contact shoe on the sandwiched side to be reduced so as to perform a work of improving a conducting characteristic between both of them with a disconnector put in an open state for a remarkably long period as compared with the concentional case.

CONSTITUTION: A clamp 20 is arranged near a contact shoe 6a on the sandwiching side while being supported by a support 2a in order to turnably support an operation axis 30 in parallel with the support 2a. A lever 41 having a pin 42 is mounted on the support 2a and a cam plate 44 having a recessed part 43 is mounted on the operation axis 30. An axis 51 is formed on the top of the support 2a, a disc 53 having a long hole 52 is fitted around an axis 51, a working plate 55 is fitted into the disc 53 so as to connect the working plate 55 to the clamp 20 through a link 56. A plate 57 is mounted on the top face of the operation axis 30 so as to connect the plate 57 to the disc 53 by a link 58 for transmitting the turn of the support 2a to the operation axis 30 by engagement of the pin 42 with the recesses part 43.