A mono-tube type hydraulic shock absorber includes a cylinder, a free piston that partitions the inside of the cylinder into a liquid chamber in which a hydraulic fluid is filled and a gas chamber in which a gas is filled, a piston slidably inserted into the cylinder, the piston partitioning the liquid chamber into two working chambers, a sealing ring provided on an outer periphery of the free piston, the sealing ring being configured to seal between the cylinder and the free piston, and a lubricating oil enclosed within the gas chamber to lubricate between the sealing ring and the cylinder.