This study considers the specificity of 3,136 Korean students' occupational preferences during secondary school and examines whether the types of high school are related to the crystallization in occupational preferences by applying binary growth models. Based on Super's developmental stage, this study shows that students largely formulate solid occupational preferences in a broad occupational scheme rather than a specific one. Around the second year of high school, students' preferences gain more specificity, and they start to formulate a pattern for specific occupational preferences. Of note is that the crystallization of occupational preferences differs by high school type. Students of vocational high schools hold specifically consistent but broadly inconsistent occupational preferences.