A method for furnishing an exhaust system of an engine in a construction machine, the exhaust system comprising: an inlet silencer member that receives exhaust gas from the engine; an outlet silencer member that discharges the exhaust gas received by the inlet member; an exhaust-gas cleaning device; and an intermediate member including a first inlet side flange and a second outlet side flange capable of being detachably coupled to the inlet member and the outlet member, respectively, by couplers (41, 42) in such respective positions that the intermediate member may be interposed, in place of the exhaust-gas cleaning device, between the inlet silencer member and the outlet silencer member, wherein the intermediate member being a tubular body that allows the exhaust gas in the inlet silencer member to flow directly to the outlet silencer member without passing through an exhaust gas cleaning material (DPF, DOC) of said exhaust-gas cleaning device in a state in which the second inlet side coupling section and the second outlet side coupling section are connected to the inlet silencer member and the outlet silencer member, respectively, characterized by forming the intermediate member to include: an outer tube including an inlet side opening and an outlet side opening in opposite ends, respectively; an inner tube disposed inside the outer tube and concentrically with the outer tube and including a circumferential wall including a plurality of exhaust-gas circulation holes; an inlet side end plate including a plurality of exhaust gas inlets; and an outlet side end plate including at least one exhaust gas outlet, and adjusting the diameters of the outer tube and the inner tube and the opening areas of the exhaust gas inlets, the at least one exhaust gas outlet, and each of the exhaust-gas circulation holes so as to generate substantially the same exhaust resistance as that of the exhaust-gas cleaning device when using the same engine. an inlet silencer member that receives exhaust gas from the engine; an outlet silencer member that discharges the exhaust gas received by the inlet member; an exhaust-gas cleaning device; and an intermediate member including a first inlet side flange and a second outlet side flange capable of being detachably coupled to the inlet member and the outlet member, respectively, by couplers (41, 42) in such respective positions that the intermediate member may be interposed, in place of the exhaust-gas cleaning device, between the inlet silencer member and the outlet silencer member, wherein the intermediate member being a tubular body that allows the exhaust gas in the inlet silencer member to flow directly to the outlet silencer member without passing through an exhaust gas cleaning material (DPF, DOC) of said exhaust-gas cleaning device in a state in which the second inlet side coupling section and the second outlet side coupling section are connected to the inlet silencer member and the outlet silencer member, respectively, characterized by forming the intermediate member to include: an outer tube including an inlet side opening and an outlet side opening in opposite ends, respectively; an inner tube disposed inside the outer tube and concentrically with the outer tube and including a circumferential wall including a plurality of exhaust-gas circulation holes; an inlet side end plate including a plurality of exhaust gas inlets; and an outlet side end plate including at least one exhaust gas outlet, and an outer tube including an inlet side opening and an outlet side opening in opposite ends, respectively; an inner tube disposed inside the outer tube and concentrically with the outer tube and including a circumferential wall including a plurality of exhaust-gas circulation holes; an inlet side end plate including a plurality of exhaust gas inlets; and an outlet side end plate including at least one exhaust gas outlet, and adjusting the diameters of the outer tube and the inner tube and the opening areas of the exhaust gas inlets, the at least one exhaust gas outlet, and each of the exhaust-gas circulation holes so as to generate substantially the same exhaust resistance as that of the exhaust-gas cleaning device when using the same engine.