J.K. Rowling’s works are of particular interest for stylistic analysis, since the author’s text is always dense with various stylistic devices. The purpose of the article is to analyze and classify the stylistic devices used by J. K. Rowling in the book “Harry Potter and the Prisoner of Azkaban”. The article discusses various approaches to the definition of the concepts of “expressive means” and “stylistic device”. The principle research method is stylistic analysis. Stylistic analysis of the book allows us to identify 230 stylistic devices, which are divided into 3 large groups: graphic and phonetico-graphic, lexical and lexico-syntactic, syntactic stylistic devices. As a distinctive feature of J. K. Rowling’s style, it seems possible to indicate the simultaneous use of heterogeneous stylistic devices in the same utterance.