A valve timing adjusting apparatus comprises a first rotating body adjusting the opening/closing timing of the intake valves, and a second rotating body adjusting the opening/closing timing of exhaust valves. A first and a second driving force transmitting members respectively have first and second endless members for power transmission. The peripheral shape of the second rotating body comprises a circumferential shape portion and cutoff shape portions whose distance from the center of rotation is smaller than the circumferential shape portion's. When the first and second rotating bodies are assembled to an internal combustion engine, the cutoff shape portions are positioned in such a rotation angle position that the first endless member for power transmission can be inserted into the gap between the first and second rotating bodies.