A product identification apparatus includes a storage device which stores a dictionary including reference data of each of a plurality of products stored in association with identification information of the product, an imaging section which captures image data of a target product, and a processor which performs a dictionary registration process. The processor extracts reference data of the target product from the image data captured by the imaging section. The storage device adds the extracted reference data to previously stored reference data in association with the identification information of the target product. Alternatively, the storage device stores the extracted reference data in association with the identification information of the target product when no reference data is previously stored in association with the identification information of the target product.