This study investigated the relationship between nonstandard employment and firm financial performance based on contingent configurational perspective (Lepak & Snell, 1999). The theory suggests a moderate level of employment externalization improve firm performance. Nonstandard work is the one form of employments. Previous studies have insisted linear relationship between nonstandard employment and firm performance. Based on various precede literatures of the relationship between nonstandard employment and firm performance, we hypothesized inverted U-shape relationship between nonstandard employment and firm financial performances. To investigate the hypothesis, we used 2007 workplace panel survey , 2009 workplace panel survey , 2011 workplace panel survey provided by Korea Labor institute. We found the curvelinear relationship between nonstandard employment and financial performance in terms of the per business profits. Furthermore, we investigated curvelinear relationship between nonstandard employment and financial performance depends on industry and firm size. We found the curvelinear relationship between nonstandard employment and the per business profits in manufacturing industry and large sized firms. However, we did not find significant relationship between nonstandard employment and the per business profits in non-manufacturing industry and small and medium sized firms. According to the result, we proposed expanded theoretical perspective in the relationship between nonstandard employment and firm performance. We suggested that a moderate ratio of nonstandard worker archive the highest level of firm performance. In addition, we insisted that the firms need to consider a reasonable ratio of nonstandard worker in the organization depend on specific organizational context. Therefore, the firm inquire various way to manage nonstandard worker such as transition of nonstandard employment to the standard employment.