PURPOSE: To smoothly perform assembly work improving durability of a cushion material by forming an outer cylinder by resin and setting the width of outside diameter of this outer cylinder in its cushion material arranging direction layer than the width of inside diameter of a bracket.

CONSTITUTION: A vibro-isolating bush 2 is interposed between a dynamic damper and a car body. A rubber-made cushion material 4 is provided in the inside of a resin-made outer cylinder 3, being arranged in its diametric direction. The width of outside diameter of the cushion material 4 in its diametric direction is set larger than the width of inside diameter of a bracket 1. When the outer cylinder 3 is forced to be press fitted to the bracket 1, the outer cylinder 3 is pressed in its cushion material arranging directional part to a corresponding part of the bracket 1. Thus assembly work is smoothly performed, enabling durability of the cushion material to be improved.