An oil-in-water type one-part hair dye composition containing components (A), (B), (C) and (D) (A) a direct dye (B) a hydrocarbon oil (C) a polyoxyalkylene-modified dimethylpolysiloxane with an HLB of 7 or higher and (D) an aromatic alcohol wherein the content ratio by mass of the component (B) to the component (C), (B)/(C) is 0.05 to 10.