The merchandise planning and development system includes a WWW server 33 for informing many and unspecified customers 3.sub.1 to 3.sub.n of merchandise planning and development information about planning and/or development of new merchandise through the Internet 20, and a news server 35 for collecting the opinion information of the customers 3.sub.1 to 3.sub.n looking up the merchandise planning information through the Internet 20. The WWW server 33 informs the customers 3.sub.1 to 3.sub.n of the merchandise information suited to the needs of the customers on the basis of the opinion information by way of the Internet 20.