To provide a dye composition having resistance to light, weather, washing, sweat and abrasion, and with which color having excellent chromaticity can be obtained in a wide range of colors, especially including standard colors such as black and drown.

The dyeing composition is obtained by adding a monocationic monoazo dye of W1-W2-N=N-W3 (wherein, W1 is a specific heterocycle; W2 is a divalent pyridine or pyridazine group; and W3 is a specific cationic heterocyclic aromatic group) to a cosmetically permissible solvent.