The antenna size while small, without deteriorating the antenna gain, it is possible to multi-resonant at the desired band of the UHF band, etc., moreover, to provide an antenna and a radio communication device capable of broadening the resonance frequency .
Antenna 1-1, and two antenna portions A1, A2, is formed on the non-ground region 101 of the substrate 100. Antenna unit A1 is an antenna unit which resonates at the resonance frequency f1, is composed of a frequency-variable circuit 3-1 and the radiation electrode 4 and the loop-shaped radiation electrode 5. Antenna unit A2 is an antenna unit which resonates at a resonance frequency f2, is constituted by the radiation electrode 4 and the frequency-variable circuit 3-2 and the radiation electrode 6 and the radiation electrode 5. Tip 61 of the radiation electrode 6 via the gap G2 near the middle portion 52 of the radiation electrode 5, the middle of the radiation electrode 5 radiation electrode 6, through capacitor C2 generated between the tip 61 and the middle portion 52 It is capacitively coupled to the part 52.