Cationic electrodeposition coating composition

A cationic electrodeposition coating composition having superior defoaming property and being capable of effectively preventing the generation of unevennes of drying is provided. A cationic electrodeposition coating composition comprising a binder resin containing a cationic epoxy resin and a block isocyanate curing agent and a defoaming agent, wherein the defoaming agent contains at least one of polyoxyalkylene compounds (A) represented by any one of the following formulae (1) to (3): ]R-(OA)n1]t-mQ[-(OA)n2-L]m (1) [R-(OA)n1]t-mQ[-(OA)n2-L-(OA)n3-Q[-(OA)n4-R]t-1]m (2) [R-(OA)n1]t-1Q-L-Q [-(OA)n2-L]t-1 (3) wherein Q is a reaction residual group formed by removing a hydrogen atom(s) from a number t of primary hydroxyl groups of nonreducing disaccharide or trisaccharide, L is the reaction residual group of isocyanate or the reaction residual group of dihalogenated alkyl, OA is an oxyalkylene group having a carbon number of 2 to 4, each of n1 to n4 is independently an integer of 2 to 40, t is an integer of 2 to 4 and m is an integer of 1 to 3 and smaller than t, but provided that the total number of OA's in a molecule is 10 to 80 per one of Q.