The invention relates to an information storage device sharing personal information of the user and the information storage device sharing method. A plaintext/cryptograph area of the information storage device of the invention is corresponded to a virtual disc path belonging to each user. When the information storage device is mounted to an information processing system, personal information of the user is verified to load plaintext/cryptograph area path and virtual disc path. The personal protection information is automatically encrypted to cryptograph protection information and unloaded to the file of the plaintext/cryptograph area when written to the virtual disc path. Therefore, personal virtual disc path dedicated for each user can be accessed and managers of device and important information can manage integrally and secure the information.