An input apparatus for a user to input an instruction into a body apparatus is disclosed. The input apparatus includes: a projection unit configured to project images of a plurality of virtual keys onto a projection area on a floor surface; a position detection unit configured to detect position information of a foot of the user put on the projection area; and a key detection unit configured to detect a virtual key corresponding to a position of the foot of the user from among the virtual keys based on information on the images of the virtual keys and a result of detection by the position detection unit.