This paper presents large-scale eigenvalue analysis of structures on parallel computer using component mode synthesis (CMS). The algorithm of the CMS used in this paper was previously developed by the authors especially for large-scale eigenvalue analysis on parallel environment. It was implemented on a parallel computer Hitachi SR2201 and the performance of the analysis system was examined. Taking full advantage of the independence of the tasks in the CMS, ideal speed up was achieved by increasing the number of CPUs. The computation time for the analysis of 8 million DOFs model with simple configuration was about 116 minutes using 64 CPUs, whereas the computation time for the analysis of 1 million DOFs model with general configuration was about 92 minutes using 241 CPUs.