A chromatic dispersion device according to the invention comprises an input/output waveguide, a plurality of first ring waveguides and a second ring waveguide. The plurality of first ring waveguides optically couple with the input/output waveguide through directional coupling and are disposed along an optical axis direction of the input/output waveguide, each ring waveguide having a predetermined FSR (free spectral range) and group delay characteristics with a peak value of the same polarity. The second ring waveguide optically couples with the input/output waveguide through directional coupling, the second ring waveguide having the predetermined FSR and group delay characteristics with a peak value of a polarity different from those of the first ring waveguides.