Young’s modulus and fracture strain of Bi2223 filaments in Bi2223/Ag/Ag alloy composite tape were investigated in detail. Tensile tests were carried out for composite tapes from which Ag alloy component was completely removed by immersing the tape in NH 4 OH and H 2 O 2 solution. In this Ag alloy removed tape, the Bi2223 filaments carried almost the entire load because the yield strength and the coefficient of work hardening of Ag were quite low, and the volume fraction of Bi2223 filament was about twice as much as that of Ag. The Young’s modulus of Bi2223 filament was simply calculated from the stress–strain curve of Ag alloy removed tapes where the Ag component stress exceeded the yield strength. The residual strain of filament was low enough to be ignored, and the fracture strain of filament was directly obtained by the fracture strain of Ag alloy removed tapes.