A method of fabricating a semiconductor device includes forming a first film on a processed film, patterning the first film into a pattern with smaller width and a space with larger width, forming a second film along upper and side surfaces of first film and an upper surface of second film, etching the second film thereby to expose upper surfaces of first film and processed film while part of second film remains along the side surface of first film, etching the first film under the condition that the first film has higher etch selectivity than the second film, etching an upper part of second film under the condition that the second film has a higher etch selectivity than the processed film, after the first film has been etched, and etching the processed film with the second film serving as mask after the upper part of second film has been etched.