We have been studying of the concentration of intellectual work, such as its quantitative evaluation method and investigation of relationship between room environment and intellectual concentration．Although the intellectual concentration is greatly affected not only by the work environment but also by the personality or mental state of individual workers, the influence has not been revealed yet. In this study, we conducted a subject experiment for the first trial where their intellectual concentration was measured quantitatively in order to investigate the relationship between worker’s personality state and degree of intellectual concentration by the analysis of experimental results.