PURPOSE: To augment the bonding properties while improving the humidity resistance of sealed electronic components by a method wherein polyphenylene sulfide as well as non-denatured silicon oil and denatured silicon oil are jointly used.

CONSTITUTION: Electronic parts are sealed with resin composition in melting viscosity not exceeding 1000 poise produced using total 20W80 weight % of silica and glass fiber exceeding mean aspect ratio of 10 as well as 20W80 weight % of polyphenylene sulfide and 0.1W10 weight %, preferably 2W10 weight %, of both nondenatured silicon oil and denatured silicon oil jointly used. Through these procedures, the bonding properties of sealing resin to a lead frame or a bonding wire can be augmented to improve the humidity resistance and the thermal cycling characteristics of sealed electronic components.