The effect of transition element (TE = Fe, Ni, Cu) doping on the particulate matter (PM) oxidation in the Ruddlesden-Popper-type (RP - type) compound La_1.5Sr_1.5Mn₂O_7−σ was investigated for a dopant concentration fixed of 0.05 %. Though there is no structural change accompanied by doping, thermogravimetry curves show the noticeable difference according to the dopant. Then, Cu doping is found to be more effective than Fe and Ni doping. Finally, it was found that La_1.5Sr_1.5Mn_1.95Cu_0.05O_7−σ is one of the promising PM oxidation catalysts for the catalyzed soot filter.