A rotational friction brake regulated by the rate of change of angular speed is disclosed. The rotational friction brake includes: a first body, a second body rotationally attached to said first body, the second body rotating around a rotational center axis of said second body, and at least one braking arm rotationally attached to said second body in a pivot point. The pivot point is eccentrically offset to said rotational center axis. The at least one braking arm comprises a braking member arranged to frictionally engage a part of said first body. The at least one braking arm has a mass center placed at a distance from said pivot point that is longer than a distance from said pivot point to said rotational center axis. The braking member is arranged to frictionally engage said part of said first body. A fishing reel comprising a rotational friction brake is also disclosed.
