A valve timing adjusting apparatus includes a driving-side rotor, a driven-side rotor, and a bias mechanism. In a first preferred embodiment, a single silicon oxide layer is placed between the silicon layer and the sapphire layer. The carrying portion has a combined hook at one end thereof. The plate is moveable over a limited adjustment range. A rigid support ring extends axially beyond the inner race axial end toward the annular section to limit axial distortion of the annular section.