A composite particle that can be easily converted to cured particle or half cured particle by the use of carbodiimide resin without changing of the configuration of matrix particle of, for example a thermoplastic resin, excelling in mechanical and functional characteristics by virtue of the reaction capability inherently possessed by a carbodiimide group. In particular, a composite particle comprising matrix particle (A) having a functional group capable of reacting with a carbodiimide group and carbodiimide resin (B), characterized in that the functional group of the matrix particle (A) couples with the carbodiimide group of the carbodiimide resin (B) and that the composite particle is provided with an outer shell layer of carbodiimide resin (B) having an average thickness diameter (L), defined by the following formula [1], ranging from 0.01 to 20 μm: L=(L2−L1)/2 [1] wherein L1 represents the average diameter of matrix particle, and L2 represents the average diameter of composite particle.