1. A design verification apparatus for verifying a design of a circuit diagram designed by utilizing circuit data that is data for the designed circuit diagram, the design verification apparatus comprising: a determination unit for repeating processes of searching a second component to be connected to a first component in a circuit diagram including network configuration of components and information on each component configured to the circuit diagram, determining whether the second component is a logically transparent component, an input and output of which are logically identical in value, and searching a component to be connected to the second component until the search component is not determined as a logically transparent component, then for extracting the search component that is not determined is a transparent component; a data creating unit for creating, based on the circuit diagram, data on a logically transparent net, which represents a configuration of a logical network in which only the extracted components are connected with one another and for creating design-verification data by adding the logically transparent net to the circuit data; a storage unit for storing the design-verification data; and a verification unit for performing design verification, by tracing the connected components on the logically transparent net of the design-verification data stored in the storage unit.