To improve responsivity of a rotary damper when switching processes, and reduce costs while simplifying a damping-force-generating device.

An outer lid 30 is attached to the outer surface of a casing 10 of the rotary damper 100. Then a first oil pathway 31 and a second oil pathway 32 are provided in parallel between the outer surface of the casing 10 and the inner surface of the outer lid 30, and each of the oil pathways connects a first oil chamber 13A to a second oil chamber 13B. Then a first check valve 41 is provided to the first oil pathway 31, and a second check valve 42 is provided to the second oil pathway 32. Then an orifice plate 50 bordering both the first oil pathway 31 and the second oil pathway 32 is attached with flexible movement.