To enhance a crime preventing power by a device capable of giving an alarm against an act of crime by an invader who tries to break a lock for a house or makes an invasion.

An alarm generator 1 is attached to an upper portion of a door or shutter by using a suspension fittings 6 and a thin thread 10 made to a ring shape is inserted to an attaching fittings 9 located at a lower portion of a box-shaped cover 7 and the thread is adjusted slightly shorter than the position of a locking hardware or a door handle. And the thin thread can be hung from the locking hardware or the door handle because a spring 8 supporting the box-shaped cover becomes longer when the thin thread is pulled down at the adjusted position. In addition, a push-button switch 5 being pressed to a box shaped cover by a contracted action of the spring is reset because the box-shaped cover is separated from the alarm generator. The setting is completed by turning a switch 4 of the alarm generator to ON.