1. A noise checking method, in designing an integrated circuit, performed on a result of cell arrangement of a plurality of cells including a standard cell and a large cell on a chip of the integrated circuit or on a result of inter-cell wiring among the plurality of cells arranged on the chip, said method comprising: extracting terminal information about one or more terminals of the large cell and wiring forbidden information about one or more wiring forbidden areas each formed on or inside of the large cell from a library which provides the terminal information and the wiring forbidden information; spuriously determining one or more internal wires of the large cell based on the terminal information and the wiring forbidden information extracted in said step of extracting, and adding the internal wires determined into chip wires to be checked; selecting an object wire to be checked and at least one affecting wire from the chip wires to which the internal wires determined are added in said step of determining; calculating a noise value representing a degree at which the at least one affecting wire induces noise onto the object wire; and carrying out a noise check on the object wire based on the noise value calculated in said step of calculating.