in an antenna and a semiconductor device including the antenna , an object is to reduce the distance between electrodes of a capacitor as much as possible , reduce the area of the electrode of the capacitor as much as possible , and prevent the suppression of response sensitivity and a response range of the semiconductor device . the present invention relates to an antenna including an antenna coil provided over a first region of a base and a capacitor which uses a second region of the base as a dielectric body and which has electrodes provided for opposite planes of the second region of the base , wherein the second region of the base is thinner than the first region of the base , and also relates to a semiconductor device including the antenna .