PURPOSE: To easily retrieve whether or not a specific circuit is included in an early stage without observation by storing the connection states of circuit elements in a circuit to be retrieved and their terminals, and collating them with each other and performing the retrieval.

CONSTITUTION: The connection points between all the circuit elements of the specific circuit and their terminals are imparted with optional user set numbers, which are inputted from an input part 1 to generate a coordinate table. A CPU 2 converts the user set numbers into predetermined internal numbers from terminals having larger electric features such as the directivity, etc., of a current. Further, a retrieval table wherein the circuit elements connected in the internal number order are made to correspond is generated. Similarly, a retrieved table wherein the respective circuit elements are made to correspond is generated for the circuit to be retrieved and stored in a storage part 4. Those retrieval table and retrieved table are collated by a comparison part 2a with each other to retrieve whether or not the specific circuit is included in the circuit to be retrieved. Thus, the connection states are only compared to enable the retrieval.