The Yb-based valence-uctuating Au-Al-Yb quasicrystal exhibits unconventional quantum critical phenomena with unusual critical indices at low temperatures at ambient pressure. Furthermore, the quantum criticality of the Au-Al-Yb quasicrystal remains robust even under hydrostatic pressure. In contrast, the Au-Al-Yb 1/1 approximant does not display quantum criticality at ambient pressure and quantum criticality appears at approximately 2.0 GPa with the same critical indices as the quasicrystal. In this study, we conducted synchrotron-radiation (SR) -based 174Yb Mossbauer spectroscopy on both the quasicrystal and 1/1 approximant, allowing us to observe di_erences in the 4f electronic states of Yb ions between the quasicrystal and 1/1 approximant.