This study explores the conditions under which graduates of Japanese teacher-training universities who are not currently working as teachers may become teachers in the future. A questionnaire survey was conducted with individuals who graduated from a teacher-training university five years prior. Text mining was performed on the collected data to determine the changes required in the Japanese education field in order to encourage these individuals to become teachers. An analysis of open-ended responses from 209 individuals indicated that the main conditions for non-teachers to become teachers were "optimized work" and "improved treatment." The former included "reducing workload," "reducing overtime," "reducing the burden of extracurricular activities," "reducing the burden of parent-teacher communication," and "reducing administrative work." The latter included "paying overtime," "increasing salary," "ensuring holidays," "improving teachers' support system," and "considering the location of work." These findings are significant because they could inform policies addressing Japan's teacher shortage.