The purpose of this study is to classify the types of manufacturing flexibility and empirically investigate the causal relationships between the classified types of manufacturing flexibility and performance, targeting component manufacturers in the automobile parts and electronic parts industries. Manufacturing flexibility is divided into production resource flexibility and product flexibility. Production resource flexibility, which aims to enhance efficiency at the production site, refers to the flexibility associated with three types of transforming resources (manpower, machinery/equipment, and production methods) among the production resources commonly referred to as the "4Ms," excluding materials, which are the transformed resource. Factor analysis results showed that production resource flexibility was divided into two first-order factors: intangible resource flexibility and tangible resource flexibility. Product flexibility was divided into three first-order factors: mix flexibility, volume flexibility, and delivery flexibility. Generally, when a firm's product flexibility is high, it can effectively respond to the complex and diverse demands of the market or customers. In this study, exploratory factor analysis was used to confirm the construct validity of the key concepts (latent variables), and second-order confirmatory factor analysis using structural equation modeling was employed to examine the unidimensionality of the constructs. Furthermore, hypothesis testing through structural model estimation resulted in all four hypotheses being accepted. Consequently, it was confirmed that production resource flexibility can be a major factor or driver for enhancing product flexibility, and that both production resource flexibility and product flexibility have a positive effect on performance, which is composed of three first-order factors: financial performance, customer performance, and manufacturing performance. Additionally, production resource flexibility indirectly contributes to performance improvement through product flexibility as a mediating factor. The theoretical significance of this study can be summarized as follows. First, this study classified manufacturing flexibility into production resource flexibility and product flexibility, and then measured the specific flexibility types belonging to each category across four dimensions: range, heterogeneity, ease, and uniformity. Second, although limited to manufacturing flexibility, this study partially contributed to the integrative research of operations management (OM) and resource-based view (RBV) by empirically demonstrating that manufacturing flexibility, as a production-domain capability of firms, positively affects various types of performance. Third, from a methodological perspective, this study was able to consistently measure key concepts such as manufacturing flexibility and performance by confining the unit of analysis to the production site, that is, the factory. The practical implications of this study can be summarized as follows. First, practitioners should pay attention to enhancing production resource flexibility in addition to improving product flexibility to respond to diverse market and customer demands. Second, practitioners should focus not merely on expanding or diversifying work scope to enhance manufacturing flexibility levels, but on ensuring that such expansion and diversification can be accomplished efficiently without additional costs or time losses.