Experimental study has been made on the oxygen transport through a Millipore filter containing hemoglobin solution. Diffusivity of oxygen was obtained from the permeation through the filter containing methemoglobin solution, instead of hemoglobin, which does not interact with oxygen and therefore does not facilitate the diffusion. On the other hand, the diffusivity of hemoglobin was estimated by the augmenting chemical reaction model which was found in a good correlation with the experimental data. Accordingly confirmation can be made on the assumption that the facilitation of oxygen is attributed to transport of oxyhemoglobin due to its concentration gradient.