A resin composition comprising an inorganic material with a thermal conductivity of 10 W/mK or higher at a temperature of 20.degree. C. and an aromatic polyester is provided. The aromatic polyester may have structural units derived from (I) 2-hydroxy-6-naphthoic acid, (II) a compound selected from hydroquinone, 4,4'-dihydroxybiphenyl and 2,6-dihydroxynaphthalene, (III) naphthalenedicarboxylic acid and (IV) a compound selected from terephthalic acid, isophthalic acid and phthalic acid.