The method of manufacturing a semiconductor device comprising: forming a first hard mask layer and a second hard mask layer on the layer to be etched (S11); a first groove-forming mask pattern forming process for forming a groove-forming mask pattern which has a first pitch, is formed of the second hard mask layer, and is used as an etching mask when forming groove patterns(S12-S14); and a first concave portion-forming mask pattern forming process for etching the first hard mask layer using the second resist pattern as an etching mask, wherein the second resist pattern is formed of the second resist layer having an opening portion that has a fourth pitch and the first organic layer having an opening portion that is connected to an opening portion of the second resist layer and has a smaller size than the opening portion of the second resist layer (S15-S18).