A native passive film is formed on the SUS304 surface at ordinary temperature and pressure^{1, 2)}. As a structural model of the film, a network-structure composed of Cr-oxide and -hydroxide has ever been proposed^{1, 3)}, but experimental evidences for the structure have not been reported yet. We examined the detailed film structure using synchrotron X-ray absorption fine structure (XAFS) and X-ray photoelectron spectroscopy (XPS). The XAFS spectra clearly showed an ordered network-structure (at least < 10 Å) of Cr(IV) oxide. Additionally, the XPS spectra indicated that the chromium oxide is transformed into a chromium oxyhydroxide such as a -O-Cr-OH- structure. These results are the first evidence that the network structure exists actually in the native passive film of SUS304.