Bi4Ca3Sr3Cu4Oyglass fibers a few centimeters in length were prepared by melt spinning. After heat treatment at 830 °C, the fibers became superconducting. The x‐ray diffraction pattern revealed that the heat‐treated fibers have the 75 K phase as the major phase and Bi2Sr2CuO6and CuO as minor phases. The resistivity measurement showed that the onset superconducting temperature of the fibers was ∼80 K.