To guide other products related to a product which is taken out in hand by a customer. The present product display rack system carries out a first step for detecting an RFID number of a product taken by a customer from desired display racks 11 to 14 based upon the detection result of the RFID reader; a second step for acquiring RFID numbers of related products having related product types and functional types relative to the product type of the RFID number from the product related information data base 260 by using the detected RFID number as a key; a third step for acquiring the product display coordinates of the product type from the product coordinate data base 250 by using the acquired RFID number of the related product as a key; and a fourth step for lighting or flickering the lamp of the lamp guiding units 30 to 33 at a position close to the acquired product display coordinates.