Democracy and populist politics are both important features of modern political system. In terms of policy-making and policy-promoting, leaders of democracy are given with positive evaluation, while those of populist politics are not. General voters' distrust and indifference to party politics, democracy and even ”politics” prompts democratic leaders to mobilize political participation and win voters' support via mass media. However, in terms of manipulating voters' preferences to gain supports, there is only a fine line between democracy and populist politics. This article mainly focuses on Prime Minister Koizumi's political manipulations to clarify differences and similarities between democracy and populist politics.