To provide an unjust unlocking suppressing/preventing device easily detachable and capable of suppressing/preventing unjust unlocking operation.

A first hook storage groove 21, a second hook storage groove 22, and a third hook storage groove 23 are formed in the key hole insertion mounting body 14 of the unjust unlocking suppressing/preventing device 10. A first hook locking stage part 31, a second hook locking stage part 32, and a third hook locking stage part 33 and a first hook retraction adjusting curved surface 34, a second hook retraction adjusting curved surface 36, and a third hook retraction adjusting curved surface 38 are formed on the cylindrical part insertion part 26 of a hook retraction adjusting drum 24 disposed at the cylindrical part 18 of the key hole insertion mounting body 14. A first hook 81, a second hook 82, and a third hook 83 are retractably stored in the first hook storage groove 21, the second hook storage groove 22, and the third hook storage groove 83 of the key hole insertion mounting body 14, respectively. A sensor 88 is incorporated in the cylindrical part 18.