This paper proposes the method of automatic design that satisfies desired specification of comparator circuit using the distributed genetic algorithm and the HSPICE optimization function. Since HSPICE optimization function depends on initial values, appropriate initial values are very important. Therefore, by using the distributed genetic algorithm, determining the appropriate initial value and performing the optimization, we can design a superior quality of comparator circuit compared with conventional method [1]. As a target value, specification of HA1631S02 is used. The results of automatic design indicate that we have succeeded in designing the comparator circuit, which satisfies almost all of the specific requirements.