In interactive evolutionary computation, it is important to reduce user fatigue and to enhance the search performance in a few generations, since fatigue has an impact on users' evaluation process. These issues also have been found in in interactive genetic algorithm (IGA). In this study, we adopt multi-parental unimodal normal distribution crossover (UNDX-$m$) to solve these problems in IGA. UNDX-$m$ generates many offspring with considering the distribution of selected parents. The next population can be generated by applying UNDX-$m$ once with more than two parent solutions. Through this mechanism, the evaluation process becomes simple manner where users only select their preferable solutions. In addition, UNDX-$m$ can generate offspring that inherit their parents' traits, which enhance the search quality. In this paper, we evaluate the effectiveness of UNDX-$m$ through the numerical experiment, by using a color combination problem in Web design.