A near infrared topographic system is an effective instrument for obtaining an image of brain activation. In the conventional mapping method, the signals detected with the source-detector pairs are simply mapped and interpolated to obtain the topographic image. It is likely that an image reconstruction algorithm using a spatial sensitivity profile will improve the spatial resolution of the topographic image. In this study, a onedimensional distribution of the absorption change in the head model is calculated from the signals detected with various intervals of source-detector pairs by the conventional mapping method and an image reconstruction algorithm using the spatial sensitivity profile to evaluate the limit of spatial resolution of topographic imaging. Small intervals of the source-detector pairs improve the position of the absorption change in the topographic image calculated by both the conventional mapping method and the reconstruction algorithm. The size of the absorption change calculated from the intensity detected with a small interval of the source-detector pairs is sufficiently improved by the image reconstruction algorithm using the spatial sensitivity profile.