In this paper, we propose a method of arc-weights calculation for a cognitive map that is composed of a number of nodes (or factors) and their links, named arcs. To calculate arc-weights precisely, we consider not only the relative weights of the arcs but also the degree of the absolute importance of the factors. We adopt AHP (Analytic Hierarchy Process) to derive the strength of causal relationships among of the factors. Furthermore, we conduct a survey with multiple experts in industry to draw the degree of absolute importance of each factor. Based on the survey results, we compensate for the strength of causal relationships. Finally, we perform a case study about the product quality issue of the A company to prove superiority of our method.