Rubber composition for sidewall and pneumatic tire using the same

The present invention aims to provide a lightweight tire without decreasing durability and to reduce rolling resistance and improve steering stability of the tire. Specifically, the present invention relates to a rubber composition for a sidewall comprising 20 to 70 parts by weight of an inorganic filler, and 5 to 35 parts by weight of polypropylene powder, based on 100 parts by weight of a rubber component, which satisfies the following equation: (amount of polypropylene powder) ≤ (amount of inorganic filler + amount of polypropylene powder) / 2.