The particulate matter reducing apparatus 1, wherein each of {HEAD ~ the filters} has a central through hole of a diameter approximately the same as or greater than that of the exhaust pipe and smaller than half the outer diameter of {TAIL ~ the filter} 
The particulate matter reducing apparatus 1 , wherein each of { HEAD ~ the filters } has a central through hole of a diameter approximately the same as or greater than that of the exhaust pipe and smaller than half the outer diameter of { TAIL ~ the filter }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL