[en] In order to achieve the imaging of scanning tunneling microscope (STM) with chemical information, we have developed the STM system combined with synchrotron radiation (SR-STM). That is, we are trying to get the effect of the SR-light illumination by an STM tip during the STM observation. In the previous work, we have succeeded to observe the x-ray absorption spectra (XAS) of Si L edge by an STM tip in the constant current operation mode. In the measurement, the clear tip height change as a function of the irradiated photon energy is observed. This result suggests that the STM can be used as a element specific analysis. However, the spatial resolution of the XAS measurement with the SR-STM, i.e. the size of the area where the STM tip is detecting the photo-induced electrons was not evident. In this paper, we will report the recent trial to measure the spatial resolution of the XAS measurement by the SR-STM. (author)