An antenna includes antenna coil having a magnetic-material core and a coil conductor. The antenna coil is arranged toward a side of a planar conductor, such as a circuit board. Of the coil conductor, a first conductor part close to a first main face of the magnetic-material core and a second conductor part close to a second main face of the magnetic-material core are provided such that the first conductor part is not over the second conductor part in view from a line in a direction normal to the first main face or the second main face of the magnetic-material core. In addition, a coil axis of the coil conductor is orthogonal to the side of the planar conductor.