Using the Korea Research Institute of Vocational Education and Training’s the Fourth Human Capital
Corporate Panel data, the research model and hypotheses were set up to investigate the effects of one of
the HRD programs named OJT in relationship affecting job satisfaction and organization commitment
among the improvement of job ability. It analyzed the meaning and relationship of the OJT, job
satisfaction and organizational commitment through previous research and empirical study, and it also
tested if the improvement of job ability’s mediated effects existed between OJT, job satisfaction and
organizational commitment. In order to research the hypotheses more accurately, the survey is processed
in accordance with gender and business scale. It shows that the OJT brings advantageous effect to job
satisfaction and job commitment. It also shows that job ability improvement plays an indirect role.
However, the effect is different depending on genders. All hypotheses apply to male, but for female, the
OJT has direct effect on job satisfaction and job commitment, and job ability improvement also has no
indirect effect. In addition, the results are different depending on company scales. For big companies, all
the hypotheses are tenable. However, for small companies, OJT affects job satisfaction but has no effect
on job ability improvement, and OJT does not affect job commitment both directly and indirectly by
improving job ability.