The invention is directed to an anti-vibration sound insulator for a suspended ceiling which is intended to be used either in residential or commercial applications. The insulator comprises a metal furring devised to be fixed to the ceiling. It also includes a central part comprising a star-shaped element having an upper vertical plate provided with an orifice and two lower plates each having extremities. These extremities are folded so as to jointly form a slide rail sized to receive and support the folded extremities of the metal furring. The central part also comprises an insulating element devised to be inserted in the upper plate orifice, this insulating element including an orifice. This latter orifice allows introducing a fixing element so as to fix the insulator beneath a floor, or against a joist supporting the floor.