The present invention provides an isostatic pressing device and a press processing method using the same; the isostatic pressing device comprises a pressure container unit which cannot be directly contacted by processed foreign matters, and comprises the following units: the pressure container with openings on two axial ends and transversely arranged; freshwater is pressed into the pressure container with the opening sealed by a cover as the first pressure medium from outer side, thus pressing processed material (like shelled foodstuff) loaded in the pressure container; the isostatic pressing device comprises a barrel, wherein the upper portion of the barrel is provided with a hole, the barrel is used for containing the processed material, and arranged in the pressure container; at least the salt water is loaded into the barrel as the second pressure medium; the first pressure medium proportion is smaller than the processed material; the second pressure medium proportion is above that of the first pressure medium.