A method of forming a pattern which comprises the steps of, forming an organosilicon film on a work film, the organosilicon film comprising an organosilicon compound having a silicon-silicon bond in a backbone chain thereof and a glass transition temperature of 0° C. or more, forming a resist pattern on the organosilicon film, and transcribing the resist pattern on the organosilicon film through an etching of the organosilicon film by making use of an etching gas containing at least one kind of atom selected from the group consisting of chlorine, bromine and iodine. The organosilicon pattern obtained by the etching is employed as a mask for patterning the work film.