A two-part foam hair dye having a first agent containing an alkali agent, a second agent containing hydrogen peroxide, and a non-aerosol foamer container, wherein the first agent contains (A), from 0.20 to 2.00 mol/kg of (B), and 0.05 mol/kg or greater of (C1) a total concentration of (C1) and (C2) in the first agent is from 0.16 to 0.50 mol/kg: and a mixture of the first agent and the second agent has a viscosity of from 1 to 300 mPa·s (A) a water-soluble cationic polymer, (B) an alkali metal ion, (C1) an oxidation dye having a phenolic hydroxyl group, and (C2) an anionic surfactant.