A hydraulic shock absorber including a piston disposed within a hollow cylinder in movable position responsive to a shock applied thereto, the piston defining a hollow vortex chamber therein, the vortex chamber being communicated with fluid chambers defined in the hollow cylinder to introduce a working fluid and to generate a vortex therein for producing an absorbing force,wherein the vortex chamber being so sized as1.ltoreq.(h.multidot.Sv/So).ltoreq.6where:h is a depth of the vortex chamber;Sv is sectional area of the vortex chamber;So is effective sectional area of the piston effecting for the fluid to increase or decrease the pressure thereof.