Disclosed is a phosphate-based inorganic material which is especially excellent in chemical resistance. Specifically disclosed is a phosphate-based inorganic material containing at least P2O5, CeO2 and Cr2O3. This phosphate-based inorganic material is characterized by containing 30-75 mol% of P2O5, 8-60 mol% of CeO2 and 1.5-15 mol% of Cr2O3. Consequently, this phosphate-based inorganic material is improved in chemical resistance when compared with conventional phosphate-based inorganic materials. In particular, this phosphate-based inorganic material has more excellent chemical resistance than a quartz glass.