PURPOSE: To obtain a PP resin composition containing PP and a specific antioxidant in a specific ratio, hardly causing fiber breakage even if spinning rate is increased, having resistance to yellowing due to nitrogen oxide gas and capable of producing fiber having excellent quality.

CONSTITUTION: This PP resin composition is constituted so that (i) an amount (x) of a partially hindered type phenolic antioxidant such as 3,9-bis[2-{3-(3-tert- butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10- tetraoxaspiro(5,5)undecane of formula I is 0.05-0.5wt.% and (ii) an amount (y) of a pentaerythrytol type phosphorus type antioxidant such as bis(2,6-di-tert- buthyl-4-methylphenyl)pentaerythritol diphosphite is 0.07-1.0wt.%, based on PP and the relationship between x and y satisfies the formula II.