The purposes of this research were : 1) to study the personal factors in lower secondary students’ decisions to study in the career Department at the Demonstration School of Ramkhamhaeng University 2) to education study in lower secondary students’ decisions to study in the career Department at the Demonstration School of Ramkhamhaeng University and 3) to individual factors affecting in lower secondary students’ decisions to study in the career Department at the Demonstration School of Ramkhamhaeng University. The population students are studying in lower secondary students’ decisions to study in the career Department at the Demonstration School of Ramkhamhaeng University of 267. The instruments used in research questionnaires and interviews. The statistics used for data analysis were frequency percentage mean standard deviation t-test and One Way ANOVA. The research found that as follows: 1) Most students were male 14 years of age by studying in lower secondary students’3/7 they have a cumulated GPA of 3:01 to 3:50 by living with his father - his mother and the aptitude of most business plans. 2) The factor in choosing in lower secondary students’ decisions to study in the career Department at the Demonstration School of Ramkhamhaeng University overall students in grade 3 with comments in agree. The first two items in order from most to least found that the side with the highest mean score the reputation of the school. The second was the instructor and minimum course content. And 3) individual factors were affecting in lower secondary students’ decisions to study in the career Department at the Demonstration School of Ramkhamhaeng University found that students with gender age year of study. The GPA and the Professional and the aptitude different affect students were learning plans and career groups school not different. Except for students with different shelters affect student learning plans and the career Department at the Demonstration School of Ramkhamhaeng University difference was statistically significant at the .05 level.