Human imitation is suggested as a useful method for humanoid robots achieving daily life tasks. For human assistance, an ability to deal with difficult tasks such as tool manipulation will be necessary, and we chose the imitation process as a solution to establish this ability. We analyzed the intelligent process of imitation and divided the task into several function elements. By implementating these function elements as different modules and integrating them, we created an imitation system which specializes in tool manipulation. In this paper, we will present the configuration of our module based system and the process flow of modules which offers functions such as environment recognition, attention control, and action emergence. As a result, a broom manipulating task was achieved by a humanoid robot.