Abstract: A handle lock device for a switch, to be mounted to a switch manipulation handle protruded through a handle manipulation opening of a case in which a switching mechanism of the toggle-type is contained, is a lock cover which has a portion elongated so as to be introduced into the handle manipulation opening, whereby the lock cover prevents sufficient handle swing to effect the switching, since one of the side surfaces of the elongated portion is adapted to abut one of the end surfaces of the handle manipulation opening before the toggle-link goes over its dead center. The handle lock device makes it possible that a single lock cover can be used to lock handles of switches having different angles in the "on" and "off" states, and also that the handle may be easily and simply locked by a locking means having a simple constitution.