A clamp is provided, including: the first clamp body, provided with a first jaw; a conductive bridge mechanism, for electrically connecting to an electrode and comprising a reciprocating assembly, an elastic engaging element, and an operable portion. The elastic engaging element is provided between the reciprocating assembly and the operable portion and is independent and separated from the reciprocating assembly. The elastic engaging element can be operated to move towards the reciprocating assembly. The reciprocating assembly can be mutually engaged and positioned with the elastic engaging element. When the elastic engaging element is positioned at a third position, the reciprocating assembly can be engaged by the elastic engaging element and thus be positioned at a second position so as to allow the first jaw to be electrically connected to the electrode; when the elastic engaging element is operated and positioned at a fourth position, the reciprocating element is not stopped by the elastic engaging element and can thus be automatically positioned at the first position and not electrically connected to the first jaw.