An operation input device includes a substrate formed of an insulator, a plurality of detecting electrodes provided on a surface of the substrate, and a controller, wherein the controller detects capacitance generated between each of the detecting electrodes and an operation body when the operation body is positioned in proximity to the substrate, and determines that a gesture operation by the operation body is performed when a duration from when the capacitance becomes a first threshold or greater to when the capacitance becomes a second threshold or greater is a predetermined value or greater, or when a length in which the operation body is moved from when the capacitance becomes the first threshold or greater to when the capacitance becomes the second threshold or greater is a predetermined value or greater, the first threshold being a threshold for the capacitance, and the second threshold being greater than the first threshold.