PURPOSE: To obtain a resin-sealed type semiconductor device being excellent in heat resistance and a thermal shock cycle characteristic and free from defects such as interface exfoliation, crack and wire open, by sealing a light-emitting element with a resin composition containing crystalline silica and having a low stress and an excellent light-transmitting property.

CONSTITUTION: A light-emitting element is sealed up with a resin composition containing crystalline silica and a light-transmitting property. The resin composition is made to contain the crystalline silica of 10 to 80wt%, while thermosetting or photosetting resin is used as the resin. The resin composition 2 is injected in a plastic mold 1 for LED coated with a parting agent, and a frame 4 whereon a light-emitting element 3 is mounted is fitted thereto by using a jig 5 for fixation, and the composition is set. The jig 5 for fixation is removed after setting, and thus a resin-sealed type semiconductor device 6 sealed up with resin can be manufactured.