The present invention relates to a dispersion compensation unit capable of compensating for both the chromatic dispersion and dispersion slope of a non-zero dispersion-shifted optical fiber. The dispersion compensation unit is formed by winding a first optical fiber and second optical fiber into coil shapes and storing them in a case. The first optical fiber has a negative chromatic dispersion D₁ and a negative dispersion slope S₁ at a wave length in use. The second optical fiber has a positive chromatic dispersion D₂ and a positive dispersion slope S₂ at the wavelength in use.