The purpose of this study was to develop a scale to measure individual teamwork competency in a group. In Study 1, we constructed a preliminary version of the teamwork competency scale consisting of five subscales: communication, team orientation, back up, monitoring, and leadership. Undergraduate students (N=409) answered these preliminary subscales. Based on the results of item analysis, a final and reliable version of the five subscales was constructed. The validity of these subscales was confirmed by confirmatory factor analysis, structural equation modeling, and multiple population analysis. In Study 2, members (N=58) of university student clubs answered these subscales. The self-evaluated scores of the members whose teamwork behavior was highly evaluated by the club leader were statistically higher than those with a lower evaluation. Study 3 addressed industrial workers (N= 76) in a company whose scores of these subscales had a moderately positive or negative correlation with other measures, including self-rated and peer-rated teamwork behavior. It was concluded that these five subscales measure different aspects of teamwork competency with a certain validity.