To install a pollution preventing curtain in underwater, without occupying large area of water surface, when a cable is buried in the bottom of the water by means of a water-surface laying ship, and a device for burying the cable in the bottom of the water.

An anchor 29 for extending a curtain is fixed in the bottom of the water behind a device 30 for burying the cable, a rear support member 27 is supported by the anchor 29 for extending the curtain, and a rear extending wire 7 is extended from a laying ship 10 and connected to a rear float body 21 via the rear support member 27. The front float body 21 is pulled toward the front the laying ship 10 via the front extending wire 6, and the rear float body 21 is pulled toward the rear with the rear support member 27 via the rear extending wire 7, so that a pollution preventing curtain 20 is opened in cylindrical shape and is installed in underwater so as to enclose the device 30 for burying. With the laying ship 10 and the burying 30 moving forward, the rear extending wire 27 is sent out from the laying ship 10, and the pollution preventing curtain 20 moves forward in a cylindrical open condition with the curtain spread in tube form.