PRODUCT MANAGEMENT METHOD

This product management method manages, by a computer, a membrane electrode assembly and a fuel cell stack which are manufactured through a joining step S of joining electrode catalyst layers to gas diffusion layers that use carbon paper as a base material. The product management method is provided with: steps (S, S) of obtaining primary feature vector data by capturing an image at a specific site of each of a plurality of gas diffusion layers and storing the obtained primary feature vector data into a storage medium; and steps (S, S, S) of comparing the feature vector data, which is obtained by capturing the image at the specific site of each of the gas diffusion layers that have undergone the steps (S, S), with a management database stored in the storage medium.