This invention provides a cationic electrodeposition coating composition which exhibits high paint stability, forms coating film excelling in conductivity, intimate adhesion, corrosion resistance, finished appearance and acid resistance, and is capable of forming uniform electrocoated film also on substrates having uneven surfaces, characterized by comprising a conductive filler dispersion paste, base resin and a curing agent, said paste being formed by dispersing a conductive filler (A) composed of high conductive carbon black (a1) and at least one conductive powder (a2) selected from furnace black, graphite and conductive whisker, using a pigment-dispersing resin (B), the composition (i) containing 30-100 wt parts of a conductive filler (A) which contains at least 2 wt parts of high conductive carbon black (a1), per 100 wt parts of combined solid content of the base resin and the curing agent, (ii) the weight ratio of the conductive powder (a2)/high conductive carbon black (a1) being within a range of 0.4-20, and (iii) the pigment-dispersing resin (B) being acrylic resin-derived pigment-dispersing resin formed by copolymerization of (meth)acrylic monomer (b1) which is modified with mono- or poly-alkylene glycol or a monoether derivative thereof; nitrogen-containing, radical-polymerizable unsaturated monomer (b2) and other radical-polymerizable unsaturated monomer (b3).