Mass production and mass consumption brings environmental problems and an exhaustion of resources. Reuse of the product parts is a solution to shift from the current society with mass production/consumption toward a sustainable recycling society. However, most consumers are able to neither find appropriate replacement parts from the market nor to provide the market with the parts they do not require any more due to the lack of detailed knowledge of the product. In order to solve this problem, we are developing a part agent system with the functions to provide advices to consumers on when and which part of the product should be exchanged and on which part is appropriate for its replacement. In this report, a function developed for the negotiation among part agents is described when two or more part agents looking for replacement parts want a same part.