In near-infrared topography, the topographic images of the brain activation considerably depend on the relative position between the probe arrangement and brain activation. The variance of topographic image due to the relative position between the brain activation and the probe arrangement is evaluated by the phantom experiment and simulation. We examined five types of probe arrangements. The variation of the topographic images measured by 15-mm probe arrangements is considerably improved in comparison with the image measured by the 30-mm probe arrangements. The images are almost independent of the relative position in case where the diameter of the brain activation is greater than 30mm.