According to one embodiment, a sensor device includes a touch panel, an input device configured such that a resonant circuit including first and second conductive materials, a magnetic field generation source disposed at a position overlapping the touch panel, and a sensor controller. Each of the first and second conductive materials is capacitively coupled to at least one of a plurality of electrodes included in the touch panel. The resonant circuit is electromagnetically coupled to the magnetic field generation source so as to resonate based on a magnetic field. The sensor controller detects positions of the first and second conductive materials on the touch panel by applying a voltage to each of the plurality of electrodes.