L’écriture fragmentaire est le lieu d’un flou théorique. Elle est tout d’abord le fruit d’une appréhension intuitive, pragmatique : est fragmentaire tout texte perçu comme tel. D’Héraclite aux surréalistes en passant par Montaigne ou les frères Schlegel, l’écriture fragmentaire est protéiforme. Cependant, dans le champ de la théorie littéraire française, elle n’est généralement envisagée que dans son versant aphoristique et définie à partir d’un corpus composé de textes au statut littéraire à la limite d’un autre champ disciplinaire (la critique, la philosophie), majoritairement en langues occidentales, relevant d’une énonciation sérieuse et factuelle dont la fragmentation relève d’une démarche consciente de pensée et d’écriture. Cette thèse a ainsi pour objectif de montrer, à travers le cas particulier de la poétique singulière du fragment chez Akutagawa Ryūnosuke, l’existence d’un fragment non purement factuel, provenant d’une aire culturelle non occidentale, qui s’inscrit plus largement dans cette écriture de la crise qu’est le fragment moderne selon Françoise Susini-Anastopoulos. Les textes d’Akutagawa qui font l’objet de cette étude sont de nature variée : narratifs, autobiographiques, factuels, fictionnels, aphoristiques ou encore poétiques, ils relèvent néanmoins d’une même esthétique fragmentaire. En confrontant ces textes d’un écrivain japonais du début du XXe siècle aux réflexions théoriques tant japonaises que françaises sur les écritures brèves discontinues, nous tentons de redéfinir les contours d’une écriture fragmentaire littéraire tout en proposant une nouvelle grille de lecture pour des textes divers pour lesquels la catégorisation générique est souvent problématique. Le fragment chez Akutagawa s’articulerait ainsi autour de deux pôles : un brouillage du cadre générique dans lequel s’inscrit le texte, ainsi qu’une énonciation ironique, souvent secondée par un usage prégnant de l’intertextualité. / Fragmentary writing is difficult to define. It is, first of all, the result of a pragmatic, intuitive understanding: a text is called fragmentary when it is perceived as such. From Heraclitus, Montaigne, the Schlegel brothers to the surrealists, fragmentary writing takes many forms. However, in French literary theory, it is often limited to aphoristic texts. Its corpus is made of literary texts mostly written in European languages, which could also belong to another field (like critic or philosophy), which are non-fictional, and where fragmentation is a conscious, voluntary process of thinking and writing.This thesis aims to show, through the concrete example of Akutagawa Ryūnosuke’s poetics of fragmentary writing, the existence of a fragment outside the fiction / non-fiction dichotomy, from a non-western cultural area, which belongs to the modern fragment as crisis literature defined by Françoise Susini-Anastopoulos.In this thesis, we look at various texts written by Akutagawa. Be they narrative, fictional, non-fictional, autobiographical, poetic or aphoristic: all these texts have a common fragmentary aesthetic, despite their diversity. By reading these texts written by a Japanese writer who lived at the beginning of the 20th century under the light of Japanese and French critical works on short and discontinuous writings, we are trying to redefine the outline of a literary fragmentary writing while suggesting a new way of reading them beyond the very different generic categories they are usually thought to belong to. Accordingly, two features could describe Akutagawa’s fragmentary writing: a problematical generic categorization deliberately constructed in the texts, and an ironic voice, which is often accompanied by intertextuality. This thesis aims to show, through the concrete example of Akutagawa Ryūnosuke’s poetics of fragmentary writing, the existence of a fragment outside of the fiction / non-fiction dichotomy, from a non-western cultural area, which belongs to the modern fragment as crisis literature defined by Françoise Susini-Anastopoulos.In this thesis, we look at various texts written by Akutagawa. Narrative, fictional, non-fictional, autobiographical, poetic, aphoristic: all the texts have, despite their diversity, a common fragmentary aesthetic. By reading these texts, written by a Japanese writer who lived at the beginning of the 20th century, under the light of Japanese and French critical works on short and discontinuous writings, we are trying to redefine the outline of a literary fragmentary writing while suggesting a new way of reading problematical texts in terms of literary genre. Accordingly, two features could describe Akutagawa’s fragmentary writing: a problematical generic categorization deliberately constructed in the text and an ironic voice, which is often accompanied by a prominent intertextuality.