Due to high job-market competition among public school teachers, half of all students who had wanted to become teachers decide to accept temporary teaching jobs after failing the teacher employment examination. However, temporary teaching positions provide less secure employment conditions compared with regular teaching jobs. This study aims to describe the process among graduates of an education department through which perceptions change with regard to becoming a temporary teacher. Nine participants who were students in a department of education and failed the teacher employment examination were interviewed (six were interviewed prior to graduation; four were interviewed after having become temporary teachers; one was interviewed both before and after becoming a temporary teacher). Kinoshita’s Modified Grounded Theory Approach is applied to explain the process through which the interviewees’ perceptions change. Participants considered temporary teaching to be a safety net for those who fail the teacher employment examination. After failing the examination themselves, however, they realized temporary teaching is nonregular employment and became concerned about not being a regular employee. Nevertheless, most of them had no choice but to accept temporary teaching positions, due to time limits on job hunting. After starting work as temporary teachers, they were shocked by the differences in job security between regular and temporary teachers, and they subsequently developed a strong desire to pass the teacher employment examination. This study concludes that, to soften the impact of failing the examination, students must understand and prepare for the employment risks facing public school teachers. Moreover, to support temporary teachers, the boards of education of prefectural and city governments, which are the employers of all teachers, must support students in passing the examinations. Lastly, the boards must adequately evaluate temporary teaching careers during the examinations.