A damper is provided which damps an applied external force in accordance with the strength of the external force (impact strength). The damper 10 comprises a vessel 20 having a cylindrical chamber 21 filled with a viscous fluid, a turn member 60 turned by the external force, a slider member 40 which is moved in the chamber 21 of the vessel 20 by turn of the turn member 60, partition member 80 engaged with the slider member 40, a coiled spring 100 for energizing the slider member 40 toward the turn member 60, and a resin cap 100 blocking an opening of the vessel 20.