Mechanical properties of the system PbO-B2O3-V2O5 low melting glass during crystallization by heat-treatment were investigated. Wettability of the system PbO-B2O3-V2O5 was excellent and appropriate for commercial sealing as a low melting solder glass. Crystals, during heat-treated at 30$0^{circ}C$ of the system PbO-B2O3-V2O5 were $eta$-4PbO.B2O3, 5PbO.4B2O3, and Pb2V2O7 mainly. The percent of crystallinity was 82$pm$5%. Mechanical properties of the system PbO-B2O3-V2O5 were influenced not only by the differences of density and coefficient of thermal expansion and the stress induced from the difference in the density and coefficient of thermal expansion between glass phase and crystals but also crystallization conditions.