The present invention relates to a compact dispersion compensator and the like. The dispersion compensator comprises a housing and an optical fiber coil. The optical fiber coil has a coiled part constituted by a dispersion-compensating optical fiber wound like a coil while being in a bundle state with its winding distortion substantially eliminated. The housing is filled with a resin surrounding the coiled part of the optical fiber coil, whereas the coiled part is held by the resin. The dispersion-compensating optical fiber constituting the optical fiber coil has a chromatic dispersion of -140 ps/nm/km or less at a wavelength of 1.55 .mu.m, whereas the housing has a volume of 500 cm.sup.3 or less. This configuration allows the dispersion compensator to attain an accumulated chromatic dispersion of -1200 ps/nm/km or more but less than -600 ps/nm at a wavelength of 1.55 .mu.m.