A dispersion-compensating fiber is provided that can compensate chromatic dispersion of a DSF in the L-band (wavelength of 1.565 .mu.m to 1.625 .mu.m). The dispersion-compensating fiber is provided with a central core segment, an intermediate core segment, a ring core segment, and a clad, which are provided in this sequence concentrically from the inside, and has refractive index profile such that the refractive indices of these segments satisfy the relationship of intermediate core segment