To provide a rotary damper in which a viscous fluid does not leak from between an inner end face of a land and an outer circumferential surface of a rotatable member, and a decrease in torque caused by an eccentric rotation of the rotating member is prevented. The rotary damper has a rotatable member being relatively rotatable with respect to a casing, the proximal portion of the rotatable member being accommodated in a chamber of the case; a ridge member extending axially along and projecting radially outwardly from an outer circumferential surface of the proximal portion of the rotatable member, the ridge member having a radially outer end face disposed for sliding contact with an inner circumferential surface of the chamber; and the land extending axially along and projecting inwardly from the inner circumferential surface of the chamber, the land having a face transverse with respect to the rotational direction of the rotatable member. The ridge member and the land divide an interior of the chamber into a compression compartment and a decompression compartment, the volume of these compartments being variable complementarily to each other in response to the relative rotation of the rotatable member and the casing. A spacer is interposed between the land and the proximal portion of the rotatable member and adapted to be pressed against the outer circumferential surface of the proximal portion and the transverse face of the land by the pressure built up in the compression compartment in response to rotation of the rotatable member.