Cover film for pen sensor and pen sensor

A cover film used together with a pen sensor including a plurality of sensor electrodes, and a sensor controller which detects a position of an active pen in reference to a distribution of signal levels each corresponding to an amount of electric charge induced in an individual one of the plurality of sensor electrodes by a pen signal transmitted from a pen tip electrode disposed at a tip of the active pen. The cover film includes a conductive resin that covers an effective area formed by the sensor electrodes for detection of the position of the active pen and that includes a substantially uniform resistance component at least within a range of the effective area. The cover film is arranged, without via a cover glass, on an upper surface of a sensor electrode group including the plurality of sensor electrodes.