User can flexibly increase in setting a bar code margin and easily confirm a bar code image relative position. Operability is improved in inputting a character string regarding the bar code. For the margin, a bar code guide giving a target size of a bar code image area is displayed in an input print preview. When the character string regarding the bar code has been already input and a bar code type is changed, the character string already input is checked against character input conditions defined by the post-change type of bar code. In inputting the characters regarding the bar code, the input characters are checked against the character input conditions, such as the character type and the defined number of characters defined by the set bar code type. Therefore, the input character is ignored or displayed in a mode in which the input character is different from other characters.