Operation input device

An operation input device, comprising:

• a substrate;
• a plurality of detecting electrodes provided on a surface of the substrate;
• a detecting unit configured to detect a capacitance that occurs between each of the detecting electrodes and an operating body in response to the operating body being brought close to the substrate;
• and
• a determining unit configured to determine whether a gesture operation by the operating body has been performed or not,
• wherein the detecting electrodes include a first electrode and a second electrode, where when the operating body is moved in a longer direction of the detecting electrodes, a capacitance value of the first electrode decreases to match an amount of movement of the operating body and a capacitance value of the second electrode increases to match the amount of movement of the operating body, and
• the determining unit determines that the operating body is stopped in a case where changes in a sum of, and a ratio between, the capacitance value of the first electrode and the capacitance value of the second electrode are lower than or equal to, or lower than predetermined values respectively, and determines that the gesture operation by the operating body has been performed in response to sensing of an operation of moving the operating body after a state in which the operating body is stopped relative to the detecting electrodes, or sensing of an operation of stopping the operating body after the operating body is moved relative to the detecting electrodes.