One hundred and thirty samples from Kanagawa Prefectural Archives were examined for pH value, brightness and moisture content. The results were discussed on the relation between the kind of sample paper and each examined value. Woody papers especially made after World War II were acidic having pH 4 on an average, and were considered to be in the advanced stage of degradation from the point of brightness. It was supposed that this kind of paper was sensitive to storage conditions. Draft archives of wood-free paper showed low pH value of around 4.5 on an average. They were typical acidic papers. A considerable amount of archives were of traditional Japanese paper. They showed pH value of 4.9 on an average and had enough strength even after degradation, because of its high initial strength. However, it is to be noted that these paper were still acidic. The reprography and drawing paper of diazo type had already degraded severely. Treatment for such copying paper should be developed separately from that of other acidic paper. Most of the archives paper were acidic and their degradation progressing. A prompt action for de-acidification of the archives paper is required.