To provide a rotating damper device compact and difficult to be influenced by an ambient temperature condition and the like.

A brake band 18 with its base end 18a locked to a base bracket 12 is wound around the peripheral surface of a rotatable drum body 16, and a ring-like base part 40a is disposed around an eccentric disc 36 of the drum body 16 so as to support a free end 40b of an arm 40 movably on a specific moving locus under the rotation of the drum body 16. The free end 40b of the arm 40 and a free end 18b of the brake band 18 are interlockingly connected through a tension spring 44.