A vibration-proof tungsten wire which forms, in cases where the diameter of the wire is D mm and when an electric current corresponding to 90% of the fusion current value is passed therethrough for 5 minutes, a wire havinga crystal grain boundary at which bubbles of 0.3 .mu.m or less in diameter are dispersed in bubble rows with lengths of (0.39/D).sup.2 .times.3 .mu.m or more arrayed in the wire axis direction of said crystal grain boundary, and bubbles of 0.2 .mu.m or less in diameter are randomly dispersed; anda crystal grain in which bubbles of 0.3 .mu.m or less in diameter are dispersed in rows with lengths of (0.39/D).sup.2 .times.30 .mu.m or more arrayed in the wire axis direction within said crystal grain, and bubbles of 0.2 .mu.m or less are randomly dispersed;a process for preparing the same; and a tungsten filament obtained from the above-defined wire. The doped tungsten wire of this invention possesses excellent vibration-proof property on lighting as well as high reliability.