a trip - wire guiding device for a protective fence is described including an elongated member attachable to ground - anchoring means intermediate the fence poles and formed with a plurality of openings through which the tensioned trip - wire are passed for maintaining them in parallel space relationship . each trip - wire is insertable into the opening via a passageway extending from the opening to the edge of the member . a common locking member is received in a channel extending longitudinally through the elongated member aligned with and passing through the passageways , the common locking member being effective to lock the trip - wires in their respective opening against removal through the passageways , but permits their longitudinal movement , such as to cause the detector means to be actuated upon a change in tension in the trip - wires , but to preclude disabling the detector means by merely fastening the tensioned trip - wires to the wire - guiding member or to the common locking member fixed thereto . in several described embodiments the elongated trip - wire guiding member is made of sheet metal , and in a further described embodiment it comprises an open spiral rod .