To notify a staff in the vicinity of belts and chains constituting a barricade disconnected due to some causes and to quickly restore and repair the barricade in a simple barricade used in a place where many customers wait their turns by forming a line at a ticket office of a station or an automatic teller machine at a bank.

The belt 3 is stored at the inside of a head part 2 of a post 1 so that the belt 3 may be drawn in the horizontal direction. In the vicinity of a drawing part 2A of the belt 3, a sensor 4 having a magnetic sensor 4 as a detection element 4A is provided. A marking member 10 such as a permanent magnet is attachably/detachably mounted on the belt 3 by a clip 10A. When the belt 3 is moved due to some causes, also the marking member 10 is moved according to the movement of the belt 3, and the sensor 4 detects the movement of the marking member 10 and notifies the effect.