A semiconductor device includes a gate electrode formed on a silicon substrate via a gate insulation film in correspondence to a channel region, source and drain regions of a p-type diffusion region formed in the silicon substrate at respective outer sides of sidewall insulation films of the gate electrode, and a pair of SiGe mixed crystal regions formed in the silicon substrate at respective outer sides of the sidewall insulation films in epitaxial relationship to the silicon substrate, the SiGe mixed crystal regions being defined by respective sidewall surfaces facing with each other, wherein, in each of the SiGe mixed crystal regions, the sidewall surface is defined by a plurality of facets forming respective, mutually different angles with respect to a principal surface of the silicon substrate.