An information input device including a touch panel configured to be provided with a touch sensor that detects a position at which a sensing object is brought close to a sensing surface. In this information input device, the touch sensor has a scanning electrode and a detecting electrode that is opposed to the scanning electrode with the intermediary of a dielectric substance, and is a capacitive sensor whose electrostatic capacitance changes if the sensing object is brought close to the detecting electrode. Furthermore, a slit is formed in a surface of the detecting electrode opposed to the scanning electrode.