The purpose of this paper is to formalize the plural business innovation cases to compare each other. In case method learning, class discussions are based on cases that summarize actual business processes. This paper presents a model to re-description formally business innovation cases written in natural language. The model we named Managerial Decision-making Description Model (MDDM). MDDM consists of less than ten kinds of symbolic components and a simple syntax, for ease of writing and reading. In MDDM we define the structure of a business as layered relationship between objectives and resources. Then MDDM illustrates business innovation as a transition in the objectives-resources relationship and expresses the role of decision making in that transition. By formally describing business innovation cases in this way, it is possible to visually compare the characteristics of individual innovation processes. The model also allows us to compare the understandings between a facilitator and learners for the same case in a case study classroom. This formal description can be applied to the outcomes of organizational simulations and business games as well as to actual business innovations. In this paper, we introduce MDDM and its examples of cases descriptions derived from an actual business case and an organizational simulation.