This invention provides a pneumatic tire having a highly improved steering stability, wherein a reinforcing layer formed by spirally winding a strip-shaped triaxial fabric or triaxial fabric-rubber composite having a width W satisfying a relation of the following formula (I): W≧2/3×31/2×(2b/a+d)  (I) [wherein d=4×(D/(πρ))1/2×10−2, D is a thickness (total dtex) of cord constituting the triaxial fabric, ρ is a density (g/cm3) of the cord constituting the triaxial fabric, and a is weaving density (cords/b mm) in one axis constituting the three axes] in a circumferential direction of the tire is disposed in one or more of a bead portion 1, a sidewall portion 2 and a belt portion 5.