When　firms　were　engaged　in　completely　different　technological　field,　using　patent　data　for　the　comparisons　of　firm　technological　capability　is　not　appropriate.　The　paper　proposes　a　statistical　method　based　on　hierarchical　clustering　analysis,　which　helps　to　explore　the　structural　characteristics　of　distribution　in　the　technological　areas,　cluster　analysis　was　employed　to　group　the　firms　into　homogeneous　categories.　With　identifying　groups　and　members　of　the　group,　judge　firms　by　their　focus　of　R&D　activities　and　the　width　of　the　technological　areas.　The　paper　uses　patent　data　in　the　ICT　as　an　example　for　the　empirical　analysis.