PURPOSE: To provide a process for producing a sealing resin composition capable of giving a cured product having high reliability and excellent heat resistance.

CONSTITUTION: A process for producing a sealing resin composition is provided which comprises mixing (A) 30-90 pts.wt. antioxidant-containing epoxy resin made by mixing a molten epoxy resin with an antioxidant with (B) 10-70 pts.wt. phenolic resin containing an antioxidant and a cure accelerator, made by mixing a molten phenolic resin with an antioxidant and a cure accelerator for epoxy resin, and (C) 50-1,000 pts.wt., per 100 pts.wt. total of components A and B, silica ground in the presence of a silanol-group-containing coupling agent and having a particle size distribution having a mean particle diameter D50 of 50 μm or below and a content of particles with a particle diameter of 150 μm or below of 95 wt.% or above.