An aromatic diazo compound having at least two groups of Formula (I) in the molecule.This aromatic diazo compound can be handled under visible light free from ultraviolet, is high in photosensitivity, and can be produced by a simple synthesis method.The diazo compound has a high solubility in organic solvents, appropriate for use as a photosensitive material for a lithographic printing plate, can be easily developed by an alkaline developing solution mainly based on an alkaline aqueous solution, and has a water solubility appropriate for use in a screen printing plate. ##STR1## wherein Z.sup.1 indicates ##STR2## wherein .phi..sup.1 is arylene or substituted arylene; and -.phi..sup.2 is >C.dbd.O, lower alkyl, lower alkylene, or aryl or substituted aryl.R.sup.1 and R.sup.2 are H, alkyl of C.sub.1 to C.sub.8, or alkyloxy of C.sub.1 to C.sub.8 ; X.sup.- is anion; and R.sup.3 indicates alkyl, saturated alkyl, aralkyl, substituted aralkyl, or a group similar to ##STR3##