A dispersion compensating optical fiber includes an uncovered dispersion compensating optical fiber containing a core and a cladding, and a resin coating which is disposed around the uncovered dispersion compensating optical fiber, wherein the resin coating has an adhesive property of 10 g/mm or less, and which includes an outer coating layer which is formed to have a thickness of 3 m or more, and the outer diameter of the uncovered dispersion compensating optical fiber is in a range from 90 to 125 m, and the outer diameter of the dispersion compensating optical fiber is in a range from 180 to 250 m.