PURPOSE: To perform selection and switching between a general dictionary and a proper noun dictionary with a small number of key operations, by operating a single key to set either one of general dictionary and proper noun dictionary modes and then switching dictionaries with operation of a single key after input of a KANA train.

CONSTITUTION: When KANA letters supplied with a KANA key 15 of a keyboard device 1 show a proper noun, an operator operates a proper noun key 17 before operation of a conversion key 16. Thus an FLAG144 of an RAM4 is set, and a retrieval mode of a proper noun dictionary 7 is set. Now if a proper noun key 14 is operated again, the proper noun retrieval mode is released. Then the retrieval mode of a general dictionary is set installed. The retrieval mode of the general dictionary is automatically set when the proper noun key is not operated from the beginning. With opeation of the key 16, the states of FLAG 1W3 are successively checked to retrieve the dictionary 7. In such a way, the modes can be easily selected and switched with a small number of operations of keys.