PURPOSE: To provide safe storage and custody by holding a box on a housing shelf in suspended condition and by providing a supporting unit for supporting the box with an alarm unit for generating alarm when the box comes in declined condition.

CONSTITUTION: A housing shelf 33 is constructed in such a manner that it is in its safe being suspended by a box supporting bar 21 for suspending a box 30, and an alarm unit 40 is equipped in the supporting bar 21. The alarm unit 40 includes an alarm circuit 45 comprising a sensor 41 staying in OFF condition with the box supporting bar 21 in horizontal position and in ON condition with the box supporting bar 21 in declined position a timer 41a for maintaining the sensor 41 in its ON condition for a predetermined period, a buzzer 42, and a switch 23. Thus an alarm is generated from the alarm unit 40 when the box supporting bar 21 is wrongfully removed from an upper locking member 3 and a lower locking member 4 so that accidents such as robbery can be prevented.