This study investigates the influences of factors such as type and degree of family leisure among parents with five day work weeks on adolescents' perceived family strengths. Its findings are based on questionnaires collected from 525 male and female parents of middle school students. Factor analysis and MANOVA were employed for data analysis and $Scheff{\acute{e}}$ tests for post-hoc analysis. The main findings were as follows. First, adolescents whose parents work five days a week were at a higher level than other adolescents in terms of finances, family ties, communication, and social ties. Second, there were no significant differences concerning adolescents' family strength by type of family leisure. Third, adolescents with more family leisure activities scored higher than others in the areas of manageable strengths, financial levels, family ties, communication, and family social ties. Fourth, among families following the five day working system, adolescents who had more family leisure activities scored higher than the others in regards to manageable strengths, financial levels, family ties, communication, and family social ties. Additionally, where adolescents thought they had fewer family leisure activities, family-oriented adolescents tended to be engaged in higher physical-activity-oriented and hobby-oriented activities in relation to manageable strengths, financial level, family ties, and communication and hobby-oriented adolescents engaged in higher than average amounts of physical-activity, strengthening family social ties in the process. Fifth, concerning families not adhering to the five day working system, adolescents who had more family leisure activities scored higher than others in terms of manageable strengths, financial levels, family ties, communication, and family social ties. As the above results indicate, family leisure activities appear to be a key factor influencing family strength. Therefore, further support should be extended toward developing new forms of family leisure and additional studies should be devoted to the subject.