The polyphenylene ether according to the present invention includes 5 to 20% by mass of a component having a molecular weight of 50,000 or more and 12 to 30% by mass of a component having a molecular weight of 8,000 or less. The resin composition according to the present invention includes the polyphenylene ether (a) and a hydrogenated block copolymer (b) prepared by hydrogenating a block copolymer including at least two polymer blocks A having a vinyl aromatic compound and at least one polymer block B having a conjugated diene compound, wherein the number average molecular weight (Mnb) of the hydrogenated block copolymer is 100,000 or less, and the number average molecular weight (MnbA) of at least one polymer block of the polymer blocks A is 8,000 or more.