1. A non-transitory computer readable recording medium storing a design support program executed by computer, the program providing information considering a range of similarity, the program comprising the steps of: storing feature associated information associating a plurality of pieces of design data that can be classified for each structure and feature data provided corresponding to each piece of the design data and representing features of the design data; extracting the feature data corresponding to the design data to be searched upon receiving the design data to be searched; checking the extracted feature data against the feature data associated with the feature associated information, ordering the design data associated with the feature associated information in descending order of similarity to the design data to be searched, retrieving at least one piece of the ordered design data; generating a classification hierarchy consisting of a plurality of pieces of classification data obtained by classifying a set of the retrieved design data based on a degree of feature similarity using the feature data associated with the feature associated information; calculating a cluster relevance ratio based on at least a number of pieces of the plurality of pieces of design data and a number of pieces of the retrieved design data; selecting the design information closely associated with the classification data by fetching the design information corresponding to the design data contained in the classification data from the design associated information associating the design data and the design information representing design know-how and skills, the calculated cluster relevance ratio of the selected design information being larger than a predetermined threshold in each cluster; and displaying the classification data in a predetermined form together with the selected design information.