In order to provide an accumulator equipped with an emergency safety mechanism that is capable of being activated at a lower pressure than when a rupture disk is disposed on part of the circumference of the peripheral surface of a stay, the accumulator has an emergency safety mechanism that immediately releases pressure inside a housing to an oil port side when the inside of the housing reaches a high temperature and high pressure in an emergency such as a fire. The emergency safety mechanism allows a fluid chamber and the oil port to communicate via a first pressure release flow passage, which is formed due to a seal holder provided with recesses and projections on part of the circumference being seated on a seating surface, and a second pressure release flow passage formed due to a rubber-like elastic body of the seal disappearing as a result of the high temperature.