Abstract: A filling material for filling into articles of bedding is made by providing a plurality of discrete fiber clusters, applying a temperature stabilizing substance to the discrete fiber clusters, mixing the discrete fiber clusters with each other, and collecting the discrete fiber clusters thereby obtaining a filling material in which the distribution of the temperature stabilizing substance is substantially even. A device (1) for producing a filling material has an application station (22) for applying a temperature stabilizing substance to discrete fiber clusters, a curing station (24) for fixing the substance, a mixer (30) for mixing the discrete fiber clusters and a collecting station (32) for collecting the fiber clusters to form the filling material in which the distribution of the temperature stabilizing substance is substantially even.