To provide a protection device for a rotary damper to protect an oil seal part, arranged in the vicinity of the bearing of a rotary shaft, from a force by a deviation load applied on the rotary shaft of a rotary damper.

An adapter 5 is provided to comprise a rotary shaft part (a shaft member 6) with which the outer peripheral surface of a rotary shaft 3 protruded from a body 2 is covered and coupled in a manner to be integrally rotatable with the same rotation center as that of the rotary shaft 3: and a fixed part (a cylinder part 7) to rotatably support the rotary shaft part and be fixed on the outer surface of the body 2. This constitution simplifies constitution and reduces a cost thereof, and protects an oil seal part, arranged in the vicinity of the bearing of a rotary shaft, from a force by a deviation load applied on the rotary shaft of the rotary damper, and improves durability of the rotary damper.