A designing method for designing an electronic component aiming at increase in designing efficiency is provided. The designing method has a step of setting a predetermined electrical characteristic, a step of determining an electric constant of the component with a first electric circuit simulation to satisfy the predetermined electrical characteristic, a step of determining a pattern shape for obtaining the electric constant, a step of retrieving and selecting an electronic component matching with the electric constant from a database, and performing layout design using the selected electronic component as a module, a step of performing a second electric circuit simulation, and a step of determining whether the electrical characteristic of the module matches with the predetermined electrical characteristic.