This thesis is the study attempting to review the phenomenon that art music is changing by ``sign value`` in 21th consumer society as critical perspective. The author examined Jean Baudrillard`s sign theory of ``consumer society``, the premise of the entire paper, and then applied the change phenomenon of current art music. All things in the consumer society meet with aesthetic things through various signs. It can be discovered in classic compilation albums and advertisements in music. Art music is given new signs, and makes specific signs in other many things. However, art music`s splendid signs actually incite the desire of difference to be differentiated with others, and above all art music of consumer society contains limited contents than various fancy signs. In short, many art musics are used in everyday life in various ways but is trapped in bubbles of image. Many post-modernists regard ``autonomy`` concept of art music as fiction and claim to shed intellectual elitism. But consumer society actually take advantage of image of art music`s autonomy in order to give special ambience. This can regard making the myth of art music again. We should look critically at art music enjoyment opportunities expansion through sign value.