To provide a manufacturing method of a polyazo compound in a high yield.

Using a diazonium salt having at least an isolated bisazo structure represented by general formula (1) as a raw material, a polyazo compound represented by general formula (2) is prepared. (wherein Ar1-Ar3 and R4 represent each independently an aryl group or heteroaryl group; n represents 1 or 2, but diazonium groups represented by n1 pieces of -N2+ are included in the substituents which at least one of Ar1-Ar3 has; M represents a hexafluorophosphoric acid ion, tetrafluoroboric acid ion, perchloric acid ion, or organic sulfonic acid ion; and n2 represents a number required to neutralize the charges in the molecule).