A packet processing device has a search engine module including an associative memory for transferring a packet on the basis of an entry mapping to route information, a first processor taking charge of a pre-search process before a process of the packet to the search engine module, and a second processor taking charge of a post-search process for executing a process of routing the packet on the basis of a search result of the search engine module. In this architecture, the packet processing device further has a table used for transferring and receiving information between the first processor in charge of the pre-search process and the second processor in charge of the post-search processor, and identifying information in a specified field of the table is transferred through the search engine module as a transparent medium.