The present invention provides a cationic electrodeposition coating composition with a rust prevention property enhanced by improving the adhesion and the blocking property of a coating film obtained from a cationic electrodeposition coating composition as compared with conventional ones. The present invention provides a cationic electrodeposition coating composition including an aminated epoxy resin and a blocked polyisocyanate curing agent, wherein the aminated epoxy resin is an aminated epoxy resin obtained by reacting an amine compound with an epoxy resin, the aminated epoxy resin has a molecular weight distribution of 2.7 or less, and a rate of elongation of an electrodeposition coating film formed by applying the cationic electrodeposition coating composition to a steel sheet such that a cured film thickness is 20 µm, followed by baking at 160°C for 15 minutes, is 0.1 to 4.5%.