We studied the effect of Oersted field (H(Oe)) on current-induced domain wall motion (CIDWM) in magnetic nanowires. We found that HOe generates spin waves. Because of interaction between domain wall (DW) and spin wave, time-dependent wall velocity is oscillatory at the early stage of wall motion. The period of the oscillatory DW motion is in antiphase with the period of out-of-plane (OOP) magnetization oscillation inside the DW. The oscillatory wall velocity is suppressed as the thickness of nanowire decreases because of strong demagnetization field.