This invention provides a radial tire for aircraft comprising a belt composed of a plurality of belt layers, wherein a total strength of the belt Tbelt [N] in a circumferential direction over its full width satisfies Tbelt/WD≧1.5×106 in which D [m] is an outer diameter of the tire and W [m] is a width of the tire, the belt is composed of at least two belt layers each containing organic fiber cords with an elongation in an extension direction under a load of 3.2 cN/dtex of 2.2-9.3%, a protection belt layer having a circumferential stiffness lower than that of the belt is disposed at an outside of the belt in a radial direction, a ratio of the circumferential stiffness of the protection belt layer to the circumferential stiffness of the belt is less than 0.5, and the protection belt layer is composed of organic fiber cords having a tensile strength at break of not less than 6.3 cN/dtex and a heat shrinkage factor of 0.5-5.0%, whereby a durability of a tread portion can be improved without damaging an excellent durability against foreign matters.