Provided are a product purchase support system (100), a product purchase support device (10), and a POS terminal device (20) that improve the efficiency of checkout processing for product sales and enhance the convenience of customers when purchasing a product. The product purchase support system (100) according to the present invention includes the product purchase support device (10) including a depth camera (12) and a first display device (13), and a POS terminal device (20) that performs checkout processing for a product. When the product purchase support device (10) detects a product selection motion of selecting a product by a customer, it identifies a product selected by the customer and generates product information related to this product, and displays the product information on the first display device (13). Further, the product purchase support device (10) outputs the product information to the POS terminal device (20).