A small antenna operating at a plurality of frequency bands includes a first conductor plane in which a first split ring resonator and a second split ring resonator that have different resonant frequencies are formed and a feed line including a first branch line, a second branch line and a branch portion. Each of the split ring resonators includes a conductor region along an opening edge of an opening formed in the first conductor plane and a split portion cutting through a portion of the conductor region. One end of the first branch line is connected to the first split ring resonator and the other end extends to the branch portion across the conductor region; one end of the second branch line is connected to the second split ring resonator and the other end extends to the branch portion across the conductor region.