An apparatus for generating an internal clock signal for acquisition of accurate synchronization is provided. The apparatus including: an input buffer for buffering the external clock signal to output a first reference clock signal; a delay compensation circuit for delaying the first reference clock signal; a forward delay array; a mirror control circuit comprising a plurality of phase detectors for detecting delayed clock signals synchronized with a second reference clock signal; a backward delay array; and an output buffer to generate an internal clock signal. An internal clock signal in accurate synchronization with the reference clock signal can be generated by minimizing the delay and distortion of the reference clock signal.