Metal filter elements were newly introduced to the high temperature filter(HTF) system in thelow- and intermediate-level radioactive waste vitrification plant. In order to evaluate theperformance of various metal materials as filter media, elements made of AISI 316L, AISI 904L,and Inconel 600 were included to the test set of filter elements. At the visual inspection to theelements performed after completion of each test, a few dark spots were observed on the surface ofsome elements. Especially they were found much more at the AISI 316L elements than others. Tocheck the dark spots are the corrosion phenomena or not, two kinds of analyses were performed tothe tested filter elements. Firstly, the surfaces or the cross sections of filter specimens cut out fromboth normal area and dark spot area of elements were analyzed by SEM/EDS. The results showedthat the dark spots were not evidences of corrosion but the deposition of sodium, sulfur and silicacompounds volatilized from waste or molten glass. Secondly, the ring tensile strength were analyzedfor the ring-shape filter specimens cut out from each kind of element. The result obtained from thestrength tested showed no evidence of corrosion as well. Conclusionally, depending on the two kinds of analysis, no evidences of corrosion were foundat the tested metal filter elements. But the dark spots formed on the surface could reduce theeffective filtering area and increase the overall pressure drop of HTF system. Thus, continuousheating inside filter housing up to dew point will be required normally. And a few long-period testshould be followed for the exact evaluation of corrosion of the metal filter elements.