According to an embodiment, an interface system includes a touch panel, a pattern detecting unit, and an identification information acquisition unit. The touch panel supports a multi-touch input. The pattern detecting unit detects a pressing pattern of a pressing portion having a predetermined shape that is provided on a mounted portion of a predetermined object to be mounted on the touch panel. The identification information acquisition unit acquires information indicated by the pressing pattern to be detected by the pattern detecting unit as identification information of the object mounted on the touch panel.