To improve the reliability of burglarproofing and to suppress the increase of the device cost required for burglarproofing.

With respect to a burglarproof device main body 2, end parts of two insertion cylinder parts 27 and 27 are projected, and lock pin assemblies 7 and 7 provided in a sensor 1 are detachably fitted into insertion cylinder parts 27 and 27. Lead cords 6 and 6 are connected to lock assemblies 7 and 7 and lead cords 6 and 6 are connected to a curl cord 4 through an enclosure 5. The curl cord 4 is subjected to spring treatment where the intermediate part of the two-core cord is spirally wound around a bar material and is heated, and it is connected to one side face of a rectangular head 3. A double coated adhesive tape 30 is stuck to the bottom of the head 3, and a part of a lever 35 of a push switch is projected through a through hole 33 opened in its center so that it can be freely moved forward and backward. A loop cord is extended from the other side face of the head 3.