The invention relates to a flame-retardant resin composition for an aluminum electric wire, the resin composition comprising: a base resin containing (A) 75 to 95 parts by weight of a resin composition containing 45 to 65 parts by weight of an olefin-based resin having a tensile modulus of 1000 to 1500 MPa, 10 to 30 parts by weight of an olefin-based resin having a D hardness of 40 to 55, and 5 to 15 parts by weight of a maleic acid-modified resin and (B) 5 to 25 parts by weight of a flexible resin, and (C) 90 to 150 parts by weight of magnesium hydroxide blended into 100 parts by weight of the base resin.