Ishizaka Yojiro`s 『Aoi sanmyaku(Blue Mountain Range)』 was published in a series in the year when a new constitution of Japan came into effect. Most of advanced studies consider that the novel is actively enlightening ``democracy`` which is a new system , delivering a message that ``A new way of thinking overcomes feudal way of thinking``. For Japan, postwar occupation period was obviously the time when Japan began the second modernization. However, the period was also the time when a new postwar value was coexisting or competing with old idea named ``established social morals and customs`` in the general public`s real life. 『Blue Mountain Range』 was actually reflecting the agony of the times seeking a future image of Japan by juxtaposing new and old values of ``feudal`` and ``modern`` in places of text. Referring to the historical background of 『Blue Mountain Range』, this study examined how new and old idea are placed in detail in the novel. This study also considered how such competition is being compromised or negotiate with each other eventually through the move and consciousness of characters.