PURPOSE: To provide a document output method smoothly outputting texts including index by outputting a blank page with the nomble added if the corresponding page is the index and the nomble is proved to be an even number and applying the next nomble to the next page.

CONSTITUTION: '1' is substituted for a nomble variable N and page offset variable P. (step A) A text directed by the page offset variable P is read in a temporary storage area. (step B) If any one of three conditions is negative at all times; (1) the page head of the text is an index control code, (2) the odd-numbered page setting is 'on', (3) the nomble variable N is an even number, the text of the corresponding page with '-N' added is outputted as it is (steps C,D,E,I,J). However, if three conditions are fulfilled, the blank page is outputted and a nomble '-4-' is applied to the blank page (steps F and G). The only nomble variable N is updated (step H), and the next index is outputted (steps I and J).