Recently, self-efficacy is one of the critical constructs that have been found to influence human decisions about behavior selection and the performance associated with the selected behavior. The construct has been widely adaopted and tested in the fields of social psychology and/or other behavioral sciences. In information system field, however, it has been hardly studied, although computer self-efficiency could have been an important factor explaining and predicting human computer usage behaviors. From this perspective, main proposes of the study are : (1) to develop a measure of computer self-efficacy, 2) to identify the factors influencing self-efficacy, and 3) to reveal the relationship between self-efficacy and computer usage behavior. By reviewing the literature, past experience, others'use, encouragement by others, and anxiety are selected as the factors influencing computer self-efficacy. Four hypotheses concerning the relationship between each of the variables and computer self-efficacy are tested by LISREL. One more hypothesis about the relationship between computer self-efficacy and computer usage is also tested. The results show that computer self-efficacy is significantly influenced by computer ansiety, encouragement by others, and computer experience, and that it is closely correlated with computer usage behavior.