A polypropylene resin composition comprising: a polypropylene resin satisfying the following requirements (A-1) and (A-2); a fiber satisfying the following requirement (B-1); and an organic flame retardant, the polypropylene resin composition satisfying the following requirement, Requirement (A-1): The polypropylene resin contains a polypropylene resin having a long-chain branched structure having the following characteristics (X-i) to (X-iv): Characteristic (X-i): The melt flow rate (230°C, 2.16 kg load) is from 0.1 to 30.0 g/10 min, Characteristic (X-ii): The molecular weight distribution Mw/Mn through GPC is from 3.0 to 10.0 and Mz/Mw through GPC is from 2.5 to 10.0, Characteristic (X-iii): The melt tension (unit: g) satisfies any of the following: log MT ≥ − 0.9 × log MFR + 0.7 or MT ≥ 15 Characteristic (X-iv): The amount of paraxylene-soluble fraction at 25°C is less than 5.0% by weight relative to the total amount of the polypropylene resin, Requirement (A-2): The polypropylene resin contains at least one polypropylene resin selected from a group consisting of the polypropylene resin having a long-chain branched structure and a polypropylene resin having the following characteristics (Y-i) to (Y-ii): Characteristic (Y-i): At least one polypropylene resin selected from a group consisting of a propylene homopolymer, a propylene-α-olefin block copolymer and a propylene-α-olefin random copolymer, which does not correspond to the polypropylene resin having a long-chain branched structure, Characteristic (Y-ii): The polypropylene resin has a melt flow rate (230°C, 2.16 kg load) of from 1.0 to 200 g/10 min, Requirement (B-1): The fiber is at least one type selected from a group consisting of a glass fiber and a carbon fiber, Requirement: The content of each component falls within a range that the polypropylene resin is from 20 to 77 parts by weight, the fiber is from 5 to 40 parts by weight, and the organic flame retardant is from 18 to 40 parts by weight, and the total content of the polypropylene resin, the fiber and the organic flame retardant is 100 parts by weight. Requirement (A-1): The polypropylene resin contains a polypropylene resin having a long-chain branched structure having the following characteristics (X-i) to (X-iv): Characteristic (X-i): The melt flow rate (230°C, 2.16 kg load) is from 0.1 to 30.0 g/10 min, Characteristic (X-ii): The molecular weight distribution Mw/Mn through GPC is from 3.0 to 10.0 and Mz/Mw through GPC is from 2.5 to 10.0, Characteristic (X-iii): The melt tension (unit: g) satisfies any of the following: log MT ≥ − 0.9 × log MFR + 0.7 or MT ≥ 15 Characteristic (X-iv): The amount of paraxylene-soluble fraction at 25°C is less than 5.0% by weight relative to the total amount of the polypropylene resin, Characteristic (X-i): The melt flow rate (230°C, 2.16 kg load) is from 0.1 to 30.0 g/10 min, Characteristic (X-ii): The molecular weight distribution Mw/Mn through GPC is from 3.0 to 10.0 and Mz/Mw through GPC is from 2.5 to 10.0, Characteristic (X-iii): The melt tension (unit: g) satisfies any of the following: log MT ≥ − 0.9 × log MFR + 0.7 or MT ≥ 15 Characteristic (X-iv): The amount of paraxylene-soluble fraction at 25°C is less than 5.0% by weight relative to the total amount of the polypropylene resin, Requirement (A-2): The polypropylene resin contains at least one polypropylene resin selected from a group consisting of the polypropylene resin having a long-chain branched structure and a polypropylene resin having the following characteristics (Y-i) to (Y-ii): Characteristic (Y-i): At least one polypropylene resin selected from a group consisting of a propylene homopolymer, a propylene-α-olefin block copolymer and a propylene-α-olefin random copolymer, which does not correspond to the polypropylene resin having a long-chain branched structure, Characteristic (Y-ii): The polypropylene resin has a melt flow rate (230°C, 2.16 kg load) of from 1.0 to 200 g/10 min, Characteristic (Y-i): At least one polypropylene resin selected from a group consisting of a propylene homopolymer, a propylene-α-olefin block copolymer and a propylene-α-olefin random copolymer, which does not correspond to the polypropylene resin having a long-chain branched structure, Characteristic (Y-ii): The polypropylene resin has a melt flow rate (230°C, 2.16 kg load) of from 1.0 to 200 g/10 min, Requirement (B-1): The fiber is at least one type selected from a group consisting of a glass fiber and a carbon fiber, Requirement: The content of each component falls within a range that the polypropylene resin is from 20 to 77 parts by weight, the fiber is from 5 to 40 parts by weight, and the organic flame retardant is from 18 to 40 parts by weight, and the total content of the polypropylene resin, the fiber and the organic flame retardant is 100 parts by weight.