We have fabricated hybrids of two-dimensional silica colloidal crystals and gold nanospheres for the development of platforms showing effective SERS phenomenon with a high spatial reproducibility. The SERS signal of 4-mercaptobenzoic acid immobilized on the hybrids was enhanced up to 10.4 times by optimizing the silica diameter, as compared with that on the gold nanospheres immobilized on a planar glass plate. We propose that the effective enhancement is induced by hot spots generated at the junction regions between the silica nanospheres.