The purpose of this study was to investigate the difference in the middle schooler's career maturity level and
career preparation behavior according to whether or not students have siblings, which are environmental family
variables and the location of their schools of the field of career counseling. For this, we divided the middle
schools in Seoul into two groups, which was the Gangnam and Gangbuk area. And after selecting 4 middle
school randomly, which was located in each region, we conducted the survey to the first and second year
students with the questionnaires about whether they have siblings or not, their gender, the examination of
self-reporting career maturity level and career preparation behavior. 328 copies of questionnaires were collected
from 350 students, and 300 students are selected as the object of study except for 28 respondents who
answered improperly. We measured their minimum, maximum, average, standard deviation etc. of their career
maturity attitude, ability and career preparation behavior. And also studied the average and standard deviation of
each sub-region of career maturity attitude, ability and career preparation behavior according to whether students
have siblings or not. As a result, there was significant difference in career maturity level and career preparation
behavior of a middle school student who has siblings or not, and there was a difference in order of the only
child, first born child, and second born child. The only child in Gangman area were generally higher on career
maturity attitude, ability and career preparation behavior than the only child in Gangbuk area depending on the school's location. There wasn't a significant difference in the career maturity level of students who have siblings
depending on the school's location. However, in the behavior of career preparation, the average of Gangnam area
students who have siblings were much higher than Gangbuk area students. In this study, we tried to provide
basic informations for understanding the needs of appropriate intervention of the middle school students' career
issues in the period of career exploration to the counselors in the field of career counseling.