Decadence is a phenomenon that people express fear from their inside, so unsound aspects appear in the social culture when the existing society is about to be collapsed. This study covered the cultural and aesthetic meaning and the role of decadence by examining the concept and phenomenon of it and analyzing the real case of expression appeared in the modern fashion. Characteristics of decadent phenomenon were divided into sexual corruption, ideality, cynicism and extreme technique, and decadent expression appeared in the fashion images was examined based on the divided phenomenon. Main results are as fellows. People bring the incidents that animals go through into relief, sticking to animal instinct when the society is on the decline. At that time, sexual decadence becomes remarkable, so voyeurism by exposure in their dress is deepen, revealing abnormal sexual propensity with bisexual tendency and sexual perversion. The real facts and appearance of people are revealed by transforming and distorting bodies for the fear of humans inside suppressed in the fin-de-siecle mood. The sense of alienation and helplessness of people anxious about the future is developed to cynicism expressing the uncertain emotion in their dress, and the formative methods of dismantlement. destruction and abrasion appear to form sickly images in the gloomy and cold mood. The intention of affirmative decadence is realized by mixing heterogeneous styles and producing new things. Extreme decorative technique and gorgeousness are even mysterious and show the highest refinement.