PURPOSE: To efficiently retrieve leaked oil into the oil tank of a retrieving boat, by connecting one end of a flexible cylindrical oil fence to the suction pump of the retrieving boat, pulling out the other free end of the fence onto water to suck the leaked oil into the fence, and gravitationally separating the oil from the water.

CONSTITUTION: The free end 26 of a flexible cylindrical oil fence 24, the other end of which is connected to the suction pump 2 of a retrieving boat 1, is put on sea water to entirely surround leaked oil. A discharge pipe 27 at the free end 26 is connected to the stern pump 3 of the retrieving boat 1. The sea water containing the leaked oil is introduced into the oil fence 24 by the suction pump 2 on the bow of the boat 1. In the fence 24, the oil is separated from the water by gravity. The separated oil is retrieved into an oil tank 23 by the stern pump 3. The leaked oil is thus efficiently retrieved on the sea.