PURPOSE: To provide excellent rotation feeling and starting performance, and improve reliability.

CONSTITUTION: A rotation damper device 1 comprises holding members 8, 9 which integrally rotate with input shafts 6, 7 rotatably supported inside liquid chambers 14, 15 formed in a case 10, an orifice 32 formed between outer circumferences of the holding members 8, 9 and inner circumferential surfaces of the liquid chambers 14, 15, pressure receiving parts 11, 12 bored to part the liquid chambers 14, 15, and communication holes 16, 17 respectively provided to communicate with the liquid chambers 14, 15 parted by the pressure receiving parts 11, 12 in which flow quantity of oil 13 is set to be larger than that of the orifice 32. Plate-shaped control valves 18, 19 for controlling the communication holes 16, 17 are freely rotatably provided on the side of one side surfaces 11c, 12c in the rotation direction of the pressure receiving parts 11, 12.