A circuit layout device of a semiconductor integrated circuit having scan chains comprises a circuit layout section for performing the circuit layout of a semiconductor integrated circuit considering a weighting factor being set for a wire of the semiconductor integrated circuit and outputting the layout data, a wire length calculation section for calculating a wire length of a scan chain from the layout data output by the circuit layout section and a wire weighting section for increasing the weighting factor of the scan chain wire based on the scan chain wire length calculated by the wire length calculation section.