The utility model provides an ultrahigh-speed mechanical switch, which comprises an insulating shell body, wherein an electromagnetic operating mechanism which is used for driving a switch pull rod to do switching-on/off motion is arranged inside the insulating shell body; the electromagnetic operating mechanism comprises a movable iron core which is in transmission connection with the switch pull rod, and a sealed cavity body which allows the movable iron core to do reciprocating movement to finish switching-on/off; the movable iron core is positioned at a switching-on position and a switching-off position respectively when moves to two ends of the sealed cavity body; the movable iron core is a moving disk which separates the sealed cavity body into two parts; and through holes which are communicated with the interior and exterior of the sealed cavity body and allow buffer media to enter or leave are formed at the switching-on/off positions or close to the switching-on/off in the circumferential cavity wall of the sealed cavity body. The ultrahigh-speed mechanical switch can effectively buffer the switch pull rod when the switch pull rod does switching-on/off motion, and avoids mechanical impact.