This device for locking an opening part (9) of a jet engine nacelle with respect to a fixed part (7, 17) comprises: means (13, 16) for locking said opening part (9) with respect to said fixed part (7, 17), means for actuating (21) these locking means that are mounted such that they can move on said opening part (9) between a closed position, in which they enable said locking means (13, 16) to be immobilized, and an open position, in which they enable these locking means (13, 16) to be released. Said actuating means comprise gripping means (21). This device comprises means (41, 43) for immobilizing, in the open position, said gripping means (21) with respect to said opening part (9) at least in the direction of movement of said opening part (9).