A removable device is removably attachable to an image forming apparatus main body. The removable device includes an information storage device, a holder, and a low frictional structure. The information storage device includes: an information storage unit that stores information to be communicated between the apparatus main body and the removable device; a terminal to be contacted with an apparatus main-body terminal, for communicating information with the apparatus main body; and a substrate that holds the information storage unit and the terminal and that includes a guide to be fitted to a protrusion provided on the apparatus main body. The holder holds the substrate such that the substrate can move, when the removable device approaches the apparatus main-body terminal, on a virtual plane intersecting with a moving direction of the removable device. The low frictional structure is arranged on a contact area between the substrate and the holder.