PURPOSE: A sealing resin composition having good moisture resistance, high heat resistance, mechanical properties, and good moldability, and being suitable for use in electronic and electric parts, prepared by mixing an epoxy resin with a xylene-modified phenolic resin and an inorganic filler at a specified mixing ratio.

CONSTITUTION: The desired sealing resin composition is obtained by using (A) an epoxy resin, (B) a xylene-modified phenolic resin of the formula (wherein R is H or an alkyl, and m>1), and (C) an inorganic filler (e.g., preferably, silica powder or alumina) as essential components. Said inorganic filler is used in an amount of 25W90wt%, based on the resin composition. The amount of the xylene-modified phenolic resin used is preferably such that the molar ratio, a/b, wherein a is the number of moles of the epoxy groups of the epoxy resin (A), and b is that of the hydroxyl groups of component (B), falls within the range of 0.1W10.