Abstract: A multitype characters processing method and terminal device is used to process coded data representing characters belonging to any one of a plurality of character sets, there being characters common to each set. One of the sets is specified as the main set and the others are specified as subsets. Sequentially received data is processed to determine whether it is common character code data. If it is common character code data, it is processed as the main set character code data; if it is not common character code data, it is processed by referring to a character set related to the data previously processed.