Abstract: A semiconductor device in which a semiconductor chip is encapsulated in an epoxy resin composition comprising (A) an epoxy resin represented by formula (I): ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 each represents an alkyl group having from 1 to 4 carbon atoms, and (B) a reaction product obtained by preliminarily reacting a silane compound represented by formula (II): ##STR2## wherein X represents a monovalent organic group having at least one functional group selected from the group consisting of a glycidyl group, an amino group, and a mercapto group; Y represents an alkoxy group having from 1 to 4 carbon atoms; and n represents 0, 1 or 2, with a phenol aralkyl resin represented by formula (III) ##STR3## wherein m represents 0 or a positive integer. The epoxy resin composition has low moisture absorption and low stress to provide a semiconductor device excellent in thermal crack resistance and moisture resistance.