PURPOSE: To enable to add title symbols, by a method wherein when a title line is designate to a titled line in an inputted composition, a serial number or a symbol is automatically added to the title line when forming a document.

CONSTITUTION: When inputting a composition in a part A1 under large-group classification, a key K3 indicating the large-group classification is operated to store a control code α into a composition buffer 7, and the composition is inputted and sequentially stored into the buffer 7. To input titles B1, B2 under small-group classification, a controlling key K4 is operated to store a control code β, and then the composition is inputted and stored. When automatically adding a serial number or a symbol to the title line, an automatic table-of-contents forming mode key K1 is operated and a printing key K2 is depressed, whereby a counter KM62 is operated to count up for each code α, a counter KM63 is operated to count up for each code β, and the serial number of the symbol is automatically added to the title line through a line output buffer 61. Accordingly, the title symbol can be added accurately and easily.