A quality management apparatus (Y6) adapted to perform quality management of a production line, wherein a production facility having a plurality of production facility members for processing a product, and an inspection apparatus adapted to inspect the product processed by the production facility are provided in the production line, wherein the production facility comprises a function of observing a plurality of observation items each of which is respectively observed when an operation in the processing of the product using a respective one of the production facility members is executed, and of self-monitoring an observation value of each of the observation items in order to detect an operation abnormality in the processing of the product; the quality management apparatus (Y6) comprising: an inspection data acquisition part configured to acquire inspection data obtained by the inspection apparatus, wherein the inspection data indicate whether the processed product has a product defect; an observation data acquisition unit configured to acquire observation data in which sthe observation value of each observation item observed with the production facility during the processing of each product is recorded; a storage unit storing a table comprising a correspondence between each of a plurality of abnormal events (Ex) that can occur in the production facility and a corresponding product defect of a plurality of product defects that can occur due to the abnormal events, and a table comprising a correspondence between each of the abnormal events (Ex) and the observation item in which a change of the observation value appears when the corresponding abnormal event occurs; a causal factor estimator configured to extract the abnormal event as a causal factor candidate when the product defect is detected, the abnormal event corresponding to the defect in the table, and to estimate whether the abnormal event is the causal factor by comparing the observation value of the observation item corresponding to the abnormal event of the causal factor candidate in the table, obtained during the processing of a defective product having the product defect to the observation value obtained during the processing of a nondefective product. an inspection data acquisition part configured to acquire inspection data obtained by the inspection apparatus, wherein the inspection data indicate whether the processed product has a product defect; an observation data acquisition unit configured to acquire observation data in which sthe observation value of each observation item observed with the production facility during the processing of each product is recorded; a storage unit storing a table comprising a correspondence between each of a plurality of abnormal events (Ex) that can occur in the production facility and a corresponding product defect of a plurality of product defects that can occur due to the abnormal events, and a table comprising a correspondence between each of the abnormal events (Ex) and the observation item in which a change of the observation value appears when the corresponding abnormal event occurs; a causal factor estimator configured to extract the abnormal event as a causal factor candidate when the product defect is detected, the abnormal event corresponding to the defect in the table, and to estimate whether the abnormal event is the causal factor by comparing the observation value of the observation item corresponding to the abnormal event of the causal factor candidate in the table, obtained during the processing of a defective product having the product defect to the observation value obtained during the processing of a nondefective product. <EOS>