We have investigated the valence-band electronic structures for a CeSi single crystal using high-resolution ultraviolet photoemission spectroscopy at 7 and 290 K. The spectra do not show a so-called tail of Kondo resonance even at 7 K. This indicates that the Kondo effect is very weak in CeSi, that is, the Kondo temperature is very low. In comparing the spectrum measured at 7 K with that at 290 K, the spectral intensity at 7 K near the Fermi edge decreases and that in the energy range 20–100 meV increases. The redistribution of the spectral intensity is related to the formation of magnetic ordering in CeSi at low temperature.