The objective of this paper is to propose a Web-based Negotiation Support System(NSS) to facilitate conflict resolution between departments in a firm. As the management environment is recently becoming more complex and competitive, the need for harmonizing department functions in a firm is increasing much more than ever. In literature, most of conflict resolution approaches have been based on a sort of behavioral concepts including regular meeting or conference. However, as the department functions are wired through the Internet, a new approach to conflict resolution using the web-based technique is deemed necessary. For this purpose, we developed a Web NSS and illustrated a typical case in which conflicts between production and marketing functions are resolved using the Web NSS.