A flexible tube 10 of the present invention is disposed downstream of a exhaust path from an engine E, and formed of an outer bellows 3 as an outer tube and an inner bellows 4 as an inner tube; pleats 4c,4c of the inner bellows 4 are smaller in depth and pitch than the pleats 3c of the outer bellows 3, and the buffering space S is provided with a gap t between the pleats bottoms of the outer bellows 3 and the pleats tops of the inner bellows 4, and further, a partition 17 that splits the exhaust path is disposed in the inner bellows 4. For this reason, sound insulation effect is improved, and the lowering of the temperature of the exhaust gas is suppressed, leading to quick temperature rise of the exhaust gas to be fed into the catalytic converter, thereby promoting the activation of the catalysts and improving the capability to purify exhaust gas, and the exhaust efficiency can be improved thereby increasing output performance of the engine.