To improve a coating state by eliminating the air reservoir at an inner space of a reinforcement rib in coating a tube to which a knuckle bracket comprising an expanded reinforcement rib is fixed, in a hydraulic buffer.

In this hydraulic buffer 10 wherein the knuckle bracket 13 is fixed to the tube 11 of the hydraulic buffer 10, and the knuckle bracket 13 comprises the reinforcement ribs 36, 37 expanded to an outer part to be separated from the tube 11, air releasing passages 38, 39 are formed for communicating inner spaces of the reinforcement brackets 36, 37 in the knuckle bracket 11, positioned at an upper side in the vertical direction, to an external space, when the tube 11 is mounted in a coating attitude.