Electron microscope, pressure control method and recording medium

A specimen-exchange chamber (50) is provided adjacent to an observation chamber (70). The specimen-exchange chamber (50) is provided therein with a glow-discharge digging unit (2), and a specimen is transferred into the specimen-exchange chamber (50). When the specimen is transferred into the specimen-exchange chamber (50), pressures in the specimen-exchange chamber (50) and the glow-discharge digging unit (2) are controlled to a first pressure by an exchange chamber pump (63) which exhausts air in the specimen-exchange chamber (50), and by a first pump (61) and a second pump (62) which exhaust air in the glow-discharge digging unit. After the pressures are reduced to the first pressure and the specimen is digged by the glow-discharge digging unit (2), a pressure in the specimen-exchange chamber (50) is controlled to a second pressure which is lower than the first pressure. Thereafter, a transfer mechanism (650) transfers the specimen into the observation chamber (70).