PURPOSE: To attain simply the sentence generation and operation capable of easy-to-see indexing by forming a font of character information of an index line into a form or size different depending on the index command automatically to output the result.

CONSTITUTION: A flag TF in a CPU is set by operating an index key K3 at first. When an index word is desired, a key data is fed to a ROM1, a Kanji (Chinese character) pattern code "Ki" of a Kanji pattern code section β of an address section α of a Kanji pattern index KP having the same code 25 as a jump code section γ 25 of the 15th address of an address section α of an index section Ind is transferred to the CPU, and since the flag TF is set, the Kanji pattern code is changed and stored in a memory M and the changed pattern "Ki" is displayed on a display device D. Similarly "Bou" is displayed. Then a line feed key K4 is operated, and then the normal document processing is conducted, the result is stored in the memory M and displayed on the display device D. Then a print key K5 is operated so as to form a required document.