A hair dye composition containing an azo dye represented by any one of the formulas (1) to (5): [wherein R1, R2a, and R2b each represents a hydrogen atom or a substituent, A and A′ each represents an aromatic heterocyclic residue (having a free valence at carbon atom thereof) and these groups have, in the structure thereof, none of a carboxy group, a sulfo group, and a quaternary ammonium group]; [R represents a coupler component, X1 to X4 represent atoms coupled together with the carbon atom sandwiched between X1 and X4 to form a 5-membered heteroaromatic ring, V1 and V2 each represents a substituent, and a1 and a2 each stands for from 0 to 3]; and [R3 represents a hydroxy group, an alkylsulfonylamino group, an arylsulfonylamino group, or —CH(R4)(R5) (R4 and R5 each representing a substituent having a Hammett's constant ? of 0.2 or greater and less than 1.4), W represents a S atom or N—R6 (R6 representing a substituent), X, Y and Z each represents a nitrogen atom or a carbon atom, R7 and R8 each represents a substituent, and b stands for from 0 to 2].