5 1 V NMR experiments have been performed to study the local magnetic and electronic properties of the vanadium oxide bronzes β-AV 6 O 1 5 (A=Na and Ca). We observed a drastic change in the 5 1 V NMR spectrum due to a charge-ordering transition in both oxides. The ground state of NaV 6 O 1 5 is found to be an antiferromagnetically ordered state, whereas that of CaV 6 O 1 5 is nonmagnetic. This is closely related with the number density of V 4 + ions and the structure of the charge ordering.