Various heavy metal oxide glasses were prepared, and the optical properties of Pr and Tm ions were investigated. Among the glasses, the infrared emissions of Pr: 1.3 μm and Tm: 1.46 μm were successfully observed in Bi 2O3-containing glasses, and such phenomena were due to the high refractive index and low phonon energy of the Bi2O3 glasses. According to the results from the Judd-Ofelt analyses, the radiative transition probabilities A of Pr: 1G4→ 3H5 transition at 1.3 μm were dependent on the refractive index n and the line strength of electric dipole transition S ed. On the other hand, A of Tm: 3H4→ 3F4 transition at 1.46 urn mainly depended on n. The Pr: 1G4 level was successfully populated by Pr/Yb co-doping, resulting in the enhancement of Pr: 1.3 μm emission. In Tm3+ doped K2O-Bi2O3-Ga2O3 glasses, the 1.46 μm emission increased in intensity with increasing Tm 2O3 content.