1. A method of checking a source code, comprising: converting the source code to an installation model by a model construction unit; converting the installation model to a generalization model by an installation-generalization model conversion unit, wherein the generalization model includes generalized program information which does not depend on a language of the source code; converting the generalization model to an abstraction model by an abstraction model conversion unit, wherein the abstraction model is in an intermediate format that does not depend on the language of the source code; converting the abstraction model to a nonfunctional constraint additional generalization model by a nonfunctional constraint addition processing unit, wherein the nonfunctional constraint addition processing unit adds a nonfunctional constraint to each function of the abstraction model based on a nonfunctional rule; converting the nonfunctional constraint additional generalization model to an inspection model by a generalization-inspection model conversion unit, wherein the inspection model is in a language of a model checking tool; converting the inspection model to an inspection code by an inspection code writing unit; and checking the inspection code by the model checking tool to determine whether the source code is validated.