A character input device sets a keyboard image and an input character display area on a touch panel, the keyboard image including a plurality of character keys each having a plurality of characters assigned thereto, and receives operation on the keyboard image. The character input device identifies a subregion including a touch detection point (P), among subregions (r) set on the basis of the defining information relating a character key (10A) detected to be touched, and sets a plurality of discriminating regions (S1-S4) so that the discriminating regions are distributed on the basis of the identified subregion, the discriminating regions individually corresponding to the plurality of characters assigned to the character key (10A). When a touch release is detected thereafter, a character corresponding to the discriminating region (S0) including the detection point (P) of the touch release is selected as an input character, and is displayed on the input character display area of the touch panel.