We have investigated chemical states and band offsets in SiNSi by photoemission spectroscopy and x-ray absorption spectroscopy. N 1s photoemission spectra in SiN for three kinds of layer-thickness films are fitted by a single component, suggesting that a nitrogen atom is surrounded by three silicon and nine nitrogen atoms for the first and the second nearest neighbor, respectively. Valence-band offsets between SiN and the Si substrates are determined to be 1.6 eV using valence-band spectra by subtracting the contribution from Si substrates. Band gap of SiN is estimated to be 5.6-5.7 eV from valence-band, N 1s core level, and N K -edge-absorption spectra. Furthermore, time-dependent measurements of N 1s photoemission spectra reveal that the x-ray irradiation time is a significant factor to determine the precise valence-band offsets excluding the differential charging effects.