Abstract <p>A ribbon of soft-magnetic high-entropy alloy Fe-Co-Ni-Si-B with the nonequiatomic composition and the thickness of ~70 μm was produced by spinning. Its structure, mechanical, tribological and magnetic properties were analyzed by experimental methods of the modern materials science. It was found that the studied material is in an amorphous (X-ray amorphous) state. The microhardness of the ribbon was HV = 8 GPa. Transmission electron microscopy on electrolytically polished foils showed that the size of structural elements of the ribbon did not exceed 10 nm. Ion etching led to partial crystallization of the foil and growth of nanocrystallites to several tens of nanometers. The tensile strength of the ribbon was more than 590 MPa at a low elongation to failure (1%). The distribution patterns of the longitudinal and transverse strain components were constructed, according to which no strain macrolocalization occurred up to fracture. The wear rate in the longitudinal direction of the ribbon was more than 4 times higher than that in the transverse direction. The magnetic properties were characterized by a hysteresis loop, with the maximum value of the specific magnetic moment being ~120 emu/g.</p>