Propagation apparatus and dispersion value setting method

A propagation apparatus comprising:

• a dispersion compensation execution unit which accepts a signal of a single wavelength from a wavelength-multiplexed signal which is received on a first transmission line, and executes dispersion compensation on the signal by inputting the accepted signal to a tunable dispersion compensator with an adjusted dispersion value;
• and
• a dispersion value calculation unit which acquires each dispersion value adjusted by a plurality of dispersion compensation execution units each associated with a different wavelength, approximates the dispersion value of the wavelength assigned to a second transmission line by using the acquired dispersion values whose signal error rates are in a tolerable range, and sets the approximated dispersion value as an initial value in a tunable dispersion compensator of the second transmission line, wherein the wavelength assigned to the second transmission line is different from the wavelength associated with the plurality of dispersion compensation execution units.