To provide a resin composition for semiconductor sealing, excellent in thermal conductivity, moldability, humidity-tolerant reliability and reflow resistance, and to provide a production method thereof and a semiconductor apparatus.

The resin composition for semiconductor sealing contains a cresol novolak type epoxy resin, phenol novolak resin, curing accelerator, silica containing at least crystalline silica of an average particle diameter of 10-60 μm, and SiC of an average particle diameter of 10-80 μm, obtained by heat treatment at ≥800°C, wherein a total content of silica and SiC is 75-90 mass%, a volume filling factor of the crystalline silica is ≥25 vol.% and ≤50 vol.%, and a volume filling factor of SiC is ≥20 vol.% and ≤37 vol.%. The production method of the resin composition and the semiconductor apparatus are provided.