Abstract: The present invention relates to a device for testing resist pressure of a vessel wherein gas is stored at a high compressed state, before the use of the vessel, and to a method for testing resist pressure of a vessel by using the testing device. The device includes: the vessel provided as an object to which a resist pressure test is carried out; an elastic tube placed in the interior of the vessel and adapted to fill a liquid into the interior thereof; a pressurizing means adapted to apply a predetermined pressure to the elastic tube to allow the elastic tube to be expanded; and a pressure gauge adapted to gauge the pressure in the interior of the vessel, wherein a gas is filled into the vessel to apply a predetermined pressure to the interior of the vessel by the expansion of the elastic tube.