The purpose of this paper is to propose a fundamental concept of the Service Productivity Simulator. In Japanese service industries, some high-performance organizations already have practiced the Service Target Costing (Fig. 3), which is a new Japanese management accounting practice for design and development of successful services. However, they need CAD for services and a new technology for scientific simulation about the future service performances such as productivity and profitability. In this paper, we try to argue a fundamental concept of the simulator with resource-usage view (Figs. 1 & 2), through building a conceptual model of typical service unit (Fig. 4).