Abstract: An installation for collecting oil or fuel spilled on the sea comprising an oil collecting stage, a first tank and a second tank as cascades, a suction pump and a final tank for separation of oil from water all of which are connected with pipes in the set forth order. The oil collecting stage comprises at least one platform holding a funnel in the center to collect mixture of the oil and water on the surface of the sea and to introduce them to the submerged first tank through a first flexible tubular pipe. The platform is provided with plural buoys which are equally spaced around the platform and connected to retractile cables linking with a descending cable at a junction. The descending cable is guided along with the first flexible pipe into the first tank to be mounted on a pulley secured to the bottom of the first tank and to be fixed to the bottom of a first float in the first tank.