A red ink for marking pens of the present invention comprises a red dye represented by the formula (III) ##STR5## (wherein each of R9 through R14 is independently --H, --CH3 or --C2 H5, R1 is --CH3 or --C2 H5, and R8 is an alkyl group or a substituted alkyl group of C6 -C18), an ethanol-soluble resin and ethanol.