In general, the idea of fun is understood to be associated with interesting things, playfulnesses, joy, pleasure, etc. The "fun culture," which seeks enjoyment and pleasure through life, is a characteristic of elements observed in today's society and culture. This exerts a powerful impacts on the business operation, marketing, and product manufacturing. Moreover, it is accepted as one of remarkable phenomena representing the changing trends of fashion in the 21st century. The objectives of this study were to analyze and categorize the fun motifs observed in fashion designer Walter Van Beirendonck 's collections, to examine their formative characteristics, and to establish academic approaches and analytic framework in studying the fun phenomenon emerging in fashion. As to research methods, this study laid a theoretical ground by reviewing the related literature and previous studies, and conducted a positive case study using the data on Walter Van Beirendonck's collections and exhibitions. According to the results of this study, the fun motifs represented in Walter Van Beirendonck's collections are largely categorized into "deviation from rules," "humorous and obscene graphic images," "introduction and transformation of heterogeneous elements," "women with male gender' etc. On the other side of Walter Van Beirendonck's fashion are sex, sexual humors, sexuality, fetishism, love, form, body, language, social phenomena, harmony between nature and life, consumerism, race, shamanism, tribal rituals, nation, cultural collision, transcendent things, science fictions, cyber Space, dream, alien, future, fairytale, fantasy etc. which are expressed by using fun motifs. Moreover, these themes are led to masculinity and fantasy.