This paper presents the fundamental design of a basic and general model of narrative structure representation for computer processing. The main goal of this study is to provide a common basis for both generative and analytic processing of narratives. In this paper, after reviewing the previous computational models of narratives from a structural perspective, we propose a hierarchical graph model in which various types of narrative elements are organized with hierarchical grouping and network-like linkage. The model is applied to each of the three structural dimensions of narratives: the ``story world,'' which is the background world structure; the ``story,'' which represents chronologically organized events as the content of a narrative; and ``discourse,'' which represents the structure used for the expression of a narrative. We also present examples of narrative structure representation based on the experimental implementation of the model.