1. An authoring apparatus, comprising: a memory that stores at least one moving image file; a display that arranges and displays time information and representative images as identifiers, respectively, indicating a plurality of scenes obtained by dividing a moving image file into predetermined segments, for each of predetermined keywords corresponding respectively to the plurality of scenes, the time information and respective images being arranged and displayed on a matrix plane, on which a time axis and an axis showing applicable levels of importance of the plurality of scenes with respect to a predetermined keyword are provided orthogonal to each other, the matrix plane having a plurality of predefined sections, each section corresponding to one of the applicable levels of importance, and said representative images being displayed in a state where each representative image is arranged and displayed in one of the predefined sections corresponding to the applicable levels of importance; a moving image reproducer that reproduces the moving image file; a keyword display that displays a list of a plurality of keywords; a keyword selector that selects a predetermined keyword from among the plurality of keywords; a keyword starter that is set per keyword and starts assigning the predetermined keyword to the moving image file; a keyword stopper that is set per keyword and stops assigning the predetermined keyword to the moving image file; a keyword assignor that converts, when there is an input from the keyword starter and the keyword stopper during reproduction of the moving image file, a moving image file corresponding to a segment between the input from the keyword starter and the input from the keyword stopper, to a scene and assigns the predetermined keyword to the scene; a graphical user interface (GUI) processor that determines, when an assigned applicable level of a scene is changed by dragging and moving a representative image from a first predefined section to a second predefined section on the matrix plane, the changed applicable level indicating importance and time information of the scene in the second predefined section to which said representative image is moved with respect to said predetermined keyword; and a metadata editor that generates metadata of the scene corresponding to the moved representative image, the metadata comprising said changed applicable level showing importance and said time information of the scene with respect to said predetermined keyword determined by said graphical user interface processor, wherein the metadata comprises the plurality of scenes, the plurality of scenes each being assigned time information, keywords to specify the scenes, applicable levels of importance, and said representative images or links of the scenes, and wherein the keyword display displays keywords with different colors or shadings per keyword and displays the identifiers on the matrix plane using a display form of a color or a shading used for the keyword corresponding to the identifier.