An accessing method which is a method for accessing a probe electrode to the standard position of the format pattern relative to a medium having a format pattern having a standard position comprises the step of scanning the probe electrode so that said probe electrode may cross over the format pattern and detecting the change in tunnel current which occurs by such scanning, and the step of detecting the standard position of the format pattern based on the change in tunnel current detected and moving the probe electrode to the standard position detected. An information processing method containing the step of scanning the probe electrode along the format pattern and reading the information by detection of the tunnel current and an information processing device therefor are also disclosed.