A touchscreen sensor includes a transparent base material, a first index-matching layer, a first transparent electrode pattern, a second index-matching layer and a first adhesive layer disposed in this order at one side of the transparent base material, and a third index-matching layer, a second transparent electrode pattern, a fourth index-matching layer and a second adhesive layer disposed in this order at another side of the transparent base material. Each of the first, second, third and fourth index-matching layers has a refractive index of 1.6 to 1.8 and a thickness of 50 nm to 150 nm.