In an end portion of a case of a portable terminal, an operation that uses a movement of an operation object perpendicular to the case is possible. A portable terminal (1) includes a movement direction determination unit (52a) that determines a direction in which an operation object is moved along a direction which includes one edge of a case of an input device and which is approximately perpendicular to one surface of the case including the edge, in the vicinity of an end portion and a side surface of the case of the input device, based on a change in a pattern of a detection signal over time indicating that the operation object is detected.