An experimental study is carried out to investigate the Reynolds number effects on the near-wake of an airfoil oscillating in pitch. An NACA 4412 airfoil is sinusoidally pitched about the quarter chord point between the angle of attack -6$^{circ}$ and +6$^{circ}$. A hot-wire anemometer is used to measure the turbulent intensity in the near-wake region of an NACA 4412 airfoil. The freestream velocities of present work are 3.4, 12.4, 26.2 m/s, and the corresponding Reynolds numbers are $5.3{ imes}10^4,;1.9{ imes}10^5,;4.1{ imes}10^5$ and the reduced frequency is 0.1. Axial turbulent intensity profiles are presented to show the Reynolds number effects on the near-wake region behind an airfoil oscillating in pitch. All the cases in these measurements show that the turbulent intensities by the change of the Reynolds number are very large at the lowest Reynolds number $R_N=5.3{ imes}10^4$; and are small at the other Reynolds number $(R_N=1.9{ imes}10^5;and;4.1{ imes}10^5)$ in the near-wake region. The significant difference of turbulent intensity between $R_N=5.3{ imes}10^4,;and;1.9{ imes}l0^5$ is observed. A critical value of the Reynolds number in the near-wake of an oscillating NACA 4412 airfoil which indicates laminar separation, no separation or turbulent separation exists in the range between $R_N=5.3{ imes}10^4;and;1.9{ imes}10^5$.