Although there are some studies on dance appreciation, few studies performed quantitative analysis on audiences’ narrative and description in order to clarify psychological impression of dances. This study focused on the artistry of "Contortion (Mongolian dance performance)," which is a art of flexibility that flexibly bends the body to the utmost limit, and investigated audiences’ impressions to performances of Contortion. Audiences were male and female college students who had no prior knowledge of Contortion and asked to answer open-ended questions about impressions of Contortion before and after watching the performances by an expert. The results of the survey were analyzed by means of text mining. Based on cluster analysis, co-occurrence network analysis, and multi-dimensional scaling, changes of impressions before and after appreciation were discussed. Before appreciation of the contortion, there were many words related to impressions with little concreteness that were associated with the word "Dancing in Mongolia". However, after the appreciation, the number of adjectives such as "beautiful" and the words "expression" increased. Therefore, it is clarified that the vague impression of "dancing" changed to the artistic impression of "expression technique".