Surface oxide layer of Fe-Cr-Al alloy was investigated to apply for metal support material of SOFCs. We already found that electrical resistance of the surface oxide layer can be decreased by La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) coating and heat-treatment. The morphology of the surface oxide layer changed to a columnar structure consisting of γ-Al2O3 polycrystal and Sr3Al2O6 growing outward in the same direction. In this study, we investigated heat-treatment condition to increase durability of the oxide layer. The Fe-Cr-Al alloy was firstly coated with LSCF and pre-heat treated in a vacuum at 1000oC for 1 h. Stability of mass gain and electrical resistance in air at 700oC was significantly improved. The morphology of the surface oxide layer was a complex structure consisting of α-Al2O3/Sr3Al2O6.