A keypad overlay for credit card machines includes a main panel, a lateral wall, a connector wall, a plurality of button receiving features, a first attachment hole, and a second attachment hole. The connector wall and the lateral wall are perimetrically positioned around the main panel. The connector wall is terminally connected to the main panel. The lateral wall is terminally connected to the main panel. The plurality of button receiving features is integrated onto the main panel. The first attachment hole and the second attachment hole are oppositely positioned of each other along the connector wall. The first attachment hole traverses through the connector wall. The second attachment hole traverses through the connector wall.

An input device includes: a key (8); and an elastic supporting member (11) supporting the key (8) in such a manner as to allow the key (8) to move in a pressing direction of the key (8), the elastic supporting member (11) including: a post section (12) protruding below a level of a bottom face of the key (8) from an edge (8a) of the key (8); and an elastic arm section (13) connected to a tip end of the post section (12) and extending along the edge (8a) of the key (8).