An encoding processing apparatus includes a first storing section for storing first encoded information and second encoded information, a second storing section for storing a table indicating association relation between the first encoded information and the second encoded information, an arithmetic section for calculating the second encoded information by reading the first encoded information stored in the first storing section and searching the table stored in the second storing section, a third storing section for storing by associating the first encoded information previously read from the first storing section and the second encoded information, a first control section for reading the second encoded information associated with the first encoded information from the third storing section, and a second control section for storing by associating the first encoded information with the second encoded information in the third storing section. The arithmetic section performs processing of searching the table stored in the second storing section and calculating the second encoded information.