A Si—SiC material of Si concentration-gradient type is obtained by melt-infiltrating Si into a molded material comprising SiC particles. The Si—SiC material has a porosity of 1.0% or less and in the Si—SiC material the Si concentration decreases gradually from the surface layer towards the innermost layer. A SiC fiber-reinforced Si—SiC composite material of Si concentration-gradient type is obtained by melt-infiltrating Si into a molded material comprising a SiC fiber and SiC particles. The composite material has a porosity of 1.0% or less and in the composite material the Si concentration decreases gradually from the surface layer towards the innermost layer. These materials are significantly improved in corrosion resistance in highly oxidative and corrosive environment, strength, and healability of defects of surface layer and innermost layer.