In software development, many kinds of knowledge are shared and reused as software patterns. Howevel; the relation analysis among software by hand is on the large scale. In this wepropose a techniquefor the automatic relation analysis among the patterns. Our technique is based on a new pattern model to treat various patterns, and utilizes exiting text processing techniques to extract patternsfrom documents and to calculate the strength of pattern relations. As a result of experiments, the system that implementsour techniquehas extracted appropriate relations among patterns without informationon relations described in original pattern documents. our system has the ability to suggest relations among patterns that the author has not noticed.