This paper argues how firms explore and exploit technological knowledge for software and service through quantitative analysis. The present investigation deals with quantitative measurements of patent information in firms of telecommunication industry and software industry in Japan. Based on patent information related to R&D alliance, technological diversity, or technological fusion in the firms, the status of exploration and acquisition of technological knowledge in the firms is described. The items that I used to describe the activities were as follows: joint patent application, IPC (International Patent Classification) code allocated for each patent, cooccurrence of the IPC among several patents, and so on. By referring to the relationship among patent information, from perspective of balancing exploration and exploitation in organizational learning, I grasp the technological trend and the activity of competitions about the concerned industry, and the applicable strategic technology management is also discussed.