The magnetization property is one of the key issues when considering the accelerator-magnet applications of Bi-2212 wires. In this work, first, the critical current densities of several types of Bi-2212 round wires were measured by the transport current method at various temperatures. Then, the magnetization of the wires was measured at various temperatures and applied field amplitudes using the SQUID magnetometer. Hysteresis loops were plotted, and the time decay of the magnetization was studied. It was observed that magnetization had various values, but the hysteresis curves and time decays of all samples had the same tendency. The equivalent filament diameter can be determined from the measured magnetization and the measured critical current density. The equivalent filament diameters are several times larger as compared with the actual filament size.