A single evaluation portion is formed by disposing a plurality of MIS transistors used for evaluation having substantially the same structure as that of an actually used MIS transistor. In the evaluation portion, the respective source regions, drain regions, and gate electrodes of the MIS transistors used for evaluation are electrically connected in common to a source pad, a drain pad, and a gate pad, respectively. If the effective gate width of the single evaluation portion exceeds a given value, variations in characteristics evaluated by the evaluation portion approach variations in the characteristics of the entire semiconductor device. The accuracy of evaluating the characteristics of the semiconductor device can thus be improved by using the evaluation portion.