Provided is an apparatus for providing a system clock synchronized to a network universally. The apparatus includes a network synchronization reference signal generating unit that outputs a reference signal for network synchronization; a network synchronization controller that generates a first control voltage that allows a first clock pulse to be in synchronization with the reference signal for network synchronization; an OVCXO that generates the first clock pulse by application of the first control voltage; a system synchronization reference signal generator that generates reference signals for system synchronization; a system synchronization controller that generates a second control voltage that allows the system clock to be in synchronization with the reference signal for system synchronization; a VCO that generates a second clock pulse by application of the second control voltage; and a system clock generator that outputs the system clock. Accordingly, it is possible to apply to systems requiring network synchronization.