An impact absorber absorbs impact energy when receiving an impact load. The impact absorber includes a fibrous structure. The fibrous structure includes a tube of which a center axis extends in a direction in which the impact load is applied and a rib that connects opposing inner surfaces of the tube. The fibrous structure is impregnated with a matrix resin. The direction in which the impact load is applied is referred to as an X direction, and a direction in which the rib connects the opposing inner surfaces of the tube is referred to as a Y direction. The tube includes a fiber layer including load direction yarns extending in the X direction and intersecting direction yarns intersecting the load direction yarns. The rib includes yarns extending only in a direction orthogonal to the X direction.