An article code reading device optically reads a code symbol on to an article and specifies the article, and decodes and outputs an article code. An image pickup image part picks up an image of an area of an article, the code symbol of which is read by the article code reading device, and outputs pickup image data. An article registration is executed by searching an article data file for a corresponding price for the article, and an extraction process extracts an exterior characteristic of an article from a the pickup image data outputted by the pickup image part. A consistency is determined between a first data obtained based on the extraction process and a second data obtained based on an output from the article code reading device, and an alarm is generated when it there is not a consistency between the first data and the second data.