An antenna includes a flexible sheet, a first coil electrode being formed on a first main surface of the flexible sheet and a second coil electrode being formed on a second main surface of the flexible sheet. Another end portion of the first coil electrode and another end portion 32B of the second coil electrode oppose each other with the flexible sheet there between. One end portion of the first coil electrode opposes an electrode pad, which has a smaller area than the one end portion, with a mounting substrate there between. One end portion of the second coil electrode and a central electrode oppose each other with the flexible sheet there between, and the central electrode opposes an electrode pad, which has a smaller area than the central electrode, with the mounting substrate there between.