In a method of confidentially outputting a delivery waybill, a seller receives an order information including a customer's personal information and transmits the order information to a product provider after removing the personal information. The product provider generates a delivery information and transmits it with a delivery waybill print request to a confidential delivery waybill server. The confidential delivery waybill server generates a combined delivery waybill information by combining the delivery information and logistics information and transmits it with the delivery waybill print request to the confidential delivery waybill agent of the seller. The confidential delivery waybill agent generates a delivery waybill by combining the combined delivery waybill information and the personal information of the customer and transmits the delivery waybill to a printer of the product provider. Finally, the product provider prints the delivery waybill including the personal information of the customer on a document.