Isolating switch

The invention relates to the technical field of air circuit breakers, in particular to an isolating switch which comprises an isolating knife, a contact knife holder and a hinge knife holder, blades of the isolating knife are provided with hinge ends and contact ends, and the contact ends are provided with spring assemblies so that the two blades can clamp contact portions on the contact knife holder during closing. The isolation knife is provided with a middle fixing assembly between the hinge structure and the spring assembly in the length direction of the blades, the middle fixing assembly comprises a distance fixing part and a fixed connecting structure, the distance fixing part is located between the two blades, the fixed connecting structure enables the two blades and the distance fixing part to be fixed together, the length of the deformable part of each blade is shortened, and the deformation of the blades is reduced. The contact end of the blade is not easy to deform, the spring assembly is matched t