Rhythm analysis is widely used for texts in a poetic form to determine the individual style of the author, but rarely used in the analysis of prose due to technical problems and human factor influence. To overcome these issues we propose an automated approach that involves the development and use of specialized software for analyzing French literary prose at various stylistic levels: phonetic, lexical, and grammatical. The methods developed for rhythm analysis and implemented in the computer application cover a variety of the phonostylistic devices: calculation of the length of the rhythmic units, finding assonance, alliteration, rhyme, various repetitions, and others. Efficiency of the approach was proved experimentally by the analysis of rhythmization devices in the novels of four French writers. It was shown that the proposed automated approach allows the researcher to analyze the text 15 times faster than using the manual approach.