From the technological point of view, it is very significant to realize a desired system by interconnecting smaller systems. Analogously, decomposition theory plays a significant role for the realization of stochastic systems. Many interesting results concerned with the decomposition of stochastic systems have been published. However, the study as for the decomposition by identical components has not been presented. This paper introduces a new concept of ε-decomposition and, using the concept, proposes a method to decompose any given stochastic system into some identical component stochastic systems.