To provide a locking-unlocking apparatus which is provided with an indoor-side locking-unlocking structure capable of preventing illegal rotational operation, and has crime preventive performance.

The locking-unlocking apparatus is comprised of a cover plate 59, a connecting shaft portion 13, a thumb turn 65, and a control plate 31. The cover plate 59 is arranged on an indoor surface of a door 3, and has an operating hole 60. The connecting shaft portion 13 is placed on an indoor side of the door 3, and interlocked to a cylinder lock 5 to be engaged with an operating member 8 for moving a lock member to and fro within a lock box 7. Further, the connecting shaft portion 13 has an engaging hole 15 formed therein. The thumb turn 65 has a connecting projection 71 formed thereon, which projection penetrates through the operating hole 60 of the cover plate 59 to be engaged with and interlocked to the engaging hole 15. The control plate 31 is positioned between the cover plate 59 and the engaging hole 15, slidably movable along the indoor surface of the door 3, and biased in one sliding direction by an urging spring 53. Further, the control plate 31 includes a sheltering portion 47 for blocking the operating hole 60 of the cover plate 59 and sheltering the engaging hole 15, and a penetrating hole portion 37 for allowing the operating hole 60 of the cover plate 59 to communicate with the engaging hole 15, to thereby bring the connecting portion 71 of the thumb turn 65 into a penetrating state.