A hydropneumatic accumulator includes a shell in which gas and fluid ports are connected, respectively, with gas and fluid reservoirs of variable volume separated by a movable separator. The gas reservoir contains a compressible regenerator that fills the gas reservoir so that the separator movement reducing the gas reservoir volume compresses the regenerator. The regenerator is made from leaf elements located transversally to the separator motion direction and dividing the gas reservoir into intercommunicating gas layers of variable depths. The regenerator is preferably made from interconnected elastic metal leaf elements to allow variation of the bending strain degree so that the local bending strains of the leaf elements should not exceed the elastic limits at any position of the separator. The efficiency of fluid power recuperation and durability of the regenerator are increased.