The present invention relates to an azo dye composition for hair dyeing that has an excellent performance as a dye for hair dyeing and proves negative in the Ames test, and also relates to a method for producing the composition. An object of the present invention is to develop a purification method for a dye composition for hair dyeing mainly containing an azo dye and proving negative in the Ames test, and to provide the dye composition for hair dyeing that is produced by applying the purification method and indicates negative in the Ames test. The dye composition for hair dyeing contains, as a main component, the azo dye having trimethylammonio, and the dye composition for hair dyeing is characterized in that the result of the Ames test is negative.