An input device provided for an apparatus (1) which is held with a hand of a person. The input device includes a plurality of input keys (5) which are operated with a finger holding the apparatus (1), wherein in a case where the apparatus (1) having the input device is held with the hand, each input key (5) situated apart from a base of the finger has a finger contact area smaller than that of each input key (5) situated close to the base of the finger.