A resin composition comprising a first polyamide resin and a second polyamide resin, the first polyamide resin being an amorphous polyamide resin comprising a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, wherein 95 % by mass or more of the first polyamide resin is the structural unit derived from a dicarboxylic acid or the structural unit derived from a diamine, 70 mol% or more of the structural unit derived from a diamine being a structural unit derived from isophorone diamine, the structural unit derived from a dicarboxylic acid comprising from 30 to 80 mol% of a structural unit derived from an α,ω-linear aliphatic dicarboxylic acid having from 8 to 14 carbon atoms, and from 70 to 20 mol% of a structural unit derived from an aromatic dicarboxylic acid, which aromatic dicarboxylic acid comprises at least one of a structural unit derived from 2,6-naphthalene-dicarboxylic acid and a structural unit derived from isophthalic acid; the second polyamide resin being an amorphous polyamide resin in which at least one type of the structural unit included in the second polyamide resin is a structural unit comprising two or more alicyclic structures, wherein 40 mol% or more of the total of the structural unit included in the second polyamide resin is the structural unit comprising two or more alicyclic structures, and a mass ratio of the second polyamide resin to the sum of the first polyamide resin and the second polyamide resin being from 10 to 90 % by mass; the content of the first polyamide resin in the resin composition being 10% by mass or more and 90% by mass or less; the content of the second polyamide resin in the resin composition being 10% by mass or more and 90% by mass or less. the first polyamide resin being an amorphous polyamide resin comprising a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid, wherein 95 % by mass or more of the first polyamide resin is the structural unit derived from a dicarboxylic acid or the structural unit derived from a diamine, 70 mol% or more of the structural unit derived from a diamine being a structural unit derived from isophorone diamine, the structural unit derived from a dicarboxylic acid comprising from 30 to 80 mol% of a structural unit derived from an α,ω-linear aliphatic dicarboxylic acid having from 8 to 14 carbon atoms, and from 70 to 20 mol% of a structural unit derived from an aromatic dicarboxylic acid, which aromatic dicarboxylic acid comprises at least one of a structural unit derived from 2,6-naphthalene-dicarboxylic acid and a structural unit derived from isophthalic acid; the second polyamide resin being an amorphous polyamide resin in which at least one type of the structural unit included in the second polyamide resin is a structural unit comprising two or more alicyclic structures, wherein 40 mol% or more of the total of the structural unit included in the second polyamide resin is the structural unit comprising two or more alicyclic structures, and a mass ratio of the second polyamide resin to the sum of the first polyamide resin and the second polyamide resin being from 10 to 90 % by mass; the content of the first polyamide resin in the resin composition being 10% by mass or more and 90% by mass or less; the content of the second polyamide resin in the resin composition being 10% by mass or more and 90% by mass or less.