A semiconductor device includes: a mounting substrate; a thin cured silicone resin material film above and in contact with the mounting substrate; and a first cured silicone resin material in contact with the thin cured silicone resin material film. In the semiconductor device, an oxygen content per unit volume in the whole region in a thickness direction of the thin cured silicone resin material film is higher than an oxygen content per unit volume in the whole region in the thickness direction of the first cured silicone resin material.