The utility model relates to a non-woven fibrous insulating material having fire-resistant properties, and is used for forming a lining layer in garments. The technical result of the proposed utility model lies in improving the fire-resistance and overall thermal resistance of an insulating material while preserving the integrity of said material. A non-woven insulating fire-resistant material for forming a lining layer in garments includes a blend of polymer fibres joined into a web by thermal bonding, and contains polymer fibres and bicomponent fibres of the concentric core-sheath variety. The bicomponent fibres have a linear density of 0.22 tex, and the polymer fibres include oxidized polyacrylonitrile fibres having a linear density of 0.17 tex, wherein the aforesaid blend contains (in mass%): 20-30% bicomponent fibres, and 70-80% oxidized polyacrylonitrile fibres. In such a blend, the ratio by mass of bicomponent fibres to oxidized polyacrylonitrile fibres is from 1:4 to 3:7. In terms of structure, the material is comprised of three layers: an upper layer, a lower layer, and an inner layer. The upper and lower layers are stronger than the inner layer and are formed by additional thermal bonding of the outer regions of the material using hot calender rolls.