PURPOSE: To provide a twin carcass type floatable flexible hose capable of easily recognize visually that a fluid is leaked between carcasses.

CONSTITUTION: This flexible hose 10 is provided with a main carcass 13, a secondary carcass 15 surrounding the main carcass 13, a buoyancy material 14 around the secondary carcass 15, and an outermost cover layer 18. The secondary carcass 15 is made to be expanded in the radial direction if fluid leaks to between the two carcasses 13, 15 through the main carcass 13. Inextensible ring-shaped reinforcements are provided at one or more localized positions along the length of the hose between the secondary carcass 15 and the outer cover 13, thereby inhibit expansion of the cover layer 18 if fluid leaks to between both the carcasses 13, 15.