A circuit layout design method capable of an LSI circuit or an electronic printed circuit board free of electromagnetic interference is provided. The layout design method according to the invention includes a quasi-stationary circuit reduction step of deviding an entire circuit represented by a net list and a part library into a plurality of quasi-stationary closed circuits having a reduced size so that an intensity of an electromagnetic wave radiated from each of the quasi-stationary closed circuits is not more than a predetermined value; a wiring constraint condition calculation step of calculating constraint conditions for each of wirings mutually connecting the plurality of quasi-stationary closed circuits so that the intensity of the electromagnetic wave radiated from each of the wirings is not more than the predetermined value; and a layout step of laying out parts and the wirings based on the net list and the parts library so as to satisfy the constraint conditions.