PURPOSE: To improve the mechanical strength and electrical properties, by adding flaky glass to an epoxy resin molding material.

CONSTITUTION: As a filler, flaky glass is added to an epoxy resin molding material. The blended flaky glass comes in firm surface contact with the epoxy resin due to its planar structure, and the obtained material exhibits excellent mechanical strength that would never be obtained by use of a one-dimensional structural linear filler or powder filler. Owing to the planar structure of the flaky glass, moisture is prevented from entering the molded material, and the electrical properties, particularly a specific volume resistance after absorption of moisture, are improved.