To provide a switch in which incorrect operation of a handle is prevented.

In the interior of an instrument body, because a joint part, an intermediate plate 11 coupled with the handle 10, and a cam 7f runs aground to a cam 11d of the intermediate plate 11, rotating motion of the intermediate plate 11 is changed into reciprocating motion, and a contactor holder 7 to open and close the joint part is housed. A lock plate 12 is retractably retained by the intermediate plate 11, a lock piece 12c is energized in the direction to protrude into the outer side from the peripheral face of the intermediate plate 11 by a lock spring 13, and the intermediate plate 11 is locked because the lock piece 12c is locked to a recess 46 for locking of the interior face of the instrument body in an OFF-position and an ON position. Then, when the handle 10 is pushed into the instrument body, because a pressing protrusion 10e of the handle 10 is contacted with the lock plate 12, and the lock piece 12c moves the lock plate 12 into the direction to retreat from the peripheral face of the intermediate cam body, a lock state of the intermediate plate 11 is released.