A hydropneumatic accumulator with a flexible porous filler intended for fluid power recuperation in hydraulic systems with a high level of pulsations includes a shell where a gas port and a fluid port are connected, respectively, with a gas reservoir and a fluid reservoir of variable volume separated by a movable separator. The flexible porous filler fills the gas reservoir so that the separator movement reducing the gas reservoir volume compresses said filler. The filler is connected with internal walls of the gas reservoir with the possibility of stretching the filler at the separator movement increasing the volume of the gas reservoir. The accumulator contains means of protection of the filler boundary layer against rupture made with the possibility of reducing local deformations of the boundary filler layer in case of jerks of the separator. Development of residual deformations of the filler during multiple recuperation cycles and destruction at non-uniform motion of the separator with strong jerks are prevented.