The article deals with the urgent task of improving the functional cost analysis in the interests of introducing a quality management system, since the traditional understanding of this analysis does not meet all the requirements of quality management. To solve the problem, a system-object approach was used, which allows presenting the system as an element "Node-Function-Object" (functional object), taking into account a wider range of input and output connections. As a result of the study, an improved method of functional cost analysis has been developed that meets the requirements of ISO 9001:2015 and allows more accurate accounting of the costs necessary to obtain the final product. An example of the decomposition of the production process by means of a system-object approach is given, which made it possible to present the production process in more detail and adequately, in accordance with the requirements of the quality management system and the real input and output links of the processes performed by functional objects.