To provide the fixing bracket structure of a hydraulic shock absorber to set the fastening axial force of a bolt and nut to a low value even when a strength is increased by increasing thickness, resulting in reduction of the bearing pressure of a bolt seat surface to improve the stability of a fastening part.

This fixing bracket structure comprises a body part 21 to be securely mounted along the outer surface of a strut outer cylinder; and a pair of right and left flange parts 22 and 22 radially protruded from the body part 21, and a plurality of bolt insertion holes are formed in the two flange parts 22 and 22. In the so formed fixing bracket structure of a hydraulic shock absorber, thickness reduction parts 26 and 26 the thicknesses of which are further decreased than that of other part are formed along an axial direction at the base parts of a pair of the right and left flange parts 22 and 22.