ROTARY DAMPER, AND BRAKE SYSTEM

Provided is a rotary damper () suitable for use as a damper for a brake pedal with a fail-safe feature. In the rotary damper () intended for a brake pedal of an automobile and configured to generate a damping torque by rotation of a casing () in a forward direction N relative a rotor (), the casing () is made of thermoplastic resin and is provided with a pair of arms () projecting radially outward so as to hold a plate () therebetween. The plate () is configured to rotate about a pedal rotation center in conjunction with the brake pedal (). Moreover, the arm () out of the arms (), which is located downstream in the forward direction, includes a curved portion () with a constant width and a supporting portion () located more distal than the curved portion () is, and is configured to support the plate () with the supporting portion ().