PURPOSE: To obtain transparent, low stress and heat resistant resin seal by sealing a semiconductor device by using an epoxy resin composition mainly comprising a bisphenol F type epoxy resin.

CONSTITUTION: A semiconductor and/or a part is sealed with an epoxy resin composition impregnated with a bisphenol F type epoxy resin, a curing agent and an accelerator. 20W100wt% is preferable in the composition as the quantity of the bisphenol F type epoxy resin compounded. A substrate such as a polybasic carboxylic acid anhydride is used as the curing agent, and it is desirable that a rate where the curing agent is compounded in the epoxy resin is kept within a range of 0.5W1.8 equivalent to one epoxy equivalent. A substance, such as tertiary amines, imidazoles, etc. is employed as the accelerator, and the quantity of the accelerator added shall be 0.05W7wt% to the sum total of the epoxy resin and the curing agent.