Pd/SiO2 composite films were fabricated by the ion-beam sputter-deposition technique using a Pd/SiO2 complex target, where the contents of Pd in the films. were changed from 5 to 22%. According to TEM micrographs, the films were found to contain nanometer sized ultrafine particles with excellent uniformity. The average sizes of the particles were estimated to be 2.7, 3.1, and 3.8 nm for Pd contents of 5, 10, and 22%, respectively, According to XPS studies, it was found that Pd atoms predominantly form a palladium silicide when the Pd concentration is lower than 5%, whereas the amount of elemental Pd increases when the Pd concentration becomes higher than 10%.