a device and a method for inputting a text message on a mobile terminal . the device includes : a user input section for allowing a user to input characters , select a menu or input a command ; a memory including an additional comment storing section ; a control section for determining whether a user inputs any additional comment after inputting a message through the user input section , reading the additional comment from the memory and inserting the additional comment to the input message to complete a text message to be sent ; and a display section for displaying any input through the user input section . the method for inputting a text message on a mobile terminal comprises : inputting a message ; determining whether a user wishes to add a comment to the input message ; and inserting an additional comment stored in a memory to the input message to complete a text message to be sent .