<p>The age of candidacy acts as a barrier that prevents youth from participating in politics as representatives. While the candidacy age has become a widely debated issue worldwide in recent years, little empirical research has examined how voters perceive youth politicians. What do voters think about very young politicians? This study investigates public attitudes toward the lower age limit for politicians. In Japan, simple public opinion polls have suggested limited support for reforming the candidacy age. However, using an experimental approach, this study finds a high level of public acceptance of youth politicians. Specifically, using a conjoint survey experiment, this study explores how candidate age influences Japanese voters’ preferences for politicians, with a particular focus on youth ages 19, 23, and 25. Participants were repeatedly presented with fictitious profiles of two candidates consisted of seven attributes including age and were asked to choose between them. While older candidates aged 79 and 66 were unpopular, voters generally accepted youth candidates—even those below Japan’s current age of candidacy—across all the three legislative bodies examined (the House of Representatives, 25; the House of Councilors, 30; and municipal councils, 25). Youth voters especially showed a strong preference for youth candidates. These findings support lowering the candidacy age in Japan from the perspective of public attitudes toward politicians, contributing to discussions on age reform. Furthermore, this article contributes methodologically to youth studies by offering an experimental approach to provide empirical evidence for policy- and law-making concerning youth political participation.</p>