Transparent nanocrystallized glasses consisting of Er2Te5O13 nanocrystals (∼100 nm size) have been prepared in 10BaO·10Er2O3·80TeO2, and load/unload displacement curves at room temperature (humidity 53%) have been measured in the penetration depth of ht=200-600 nm using a Vickers nanoindentation technique. The values (4.0-9.4±0.1 GPa) of universal (dynamic) hardness (Hu) in the nanocrystallized glasses are larger than those (Hu=2.7-6.5±0.1 GPa) in the precursor glass and are slightly smaller than those (Hu=4.4-9.7±0.1 GPa) in the opaque crystallized glass consisting of Er2TeO6 crystals. The elastic recoveries during unloading are 0.53-0.61, being almost the same as those in the precursor and opaque crystallized glasses. The elastic Ue and plastic Up deformation energies at ht=500 nm in the nanocrystallized glasses are estimated to be Ue=106 and Up=91±3 kJmol-1, respectively. These values are larger than those of the precursor glass (Ue=83 and Up=57±3 kJmol-1), suggesting that the deformation energy during loading in TeO2-based glasses is largely increased due to nanocrystallization. The main origin of plastic deformation at ht<600 nm is considered to be densification.