[Problem to be Solved]To provide an antenna which can be used in a wide band.[Solution]An antenna 10A includes a dielectric substrate 11, an unbalanced power supply member 12 having a non-power supply unit 23 and a power supply unit 24, a resonance conductor 13 having a connection area 26, a first resonance area 27 and a second resonance area 28, a grounding conductor 14 having a first ground area 32 and a second ground area 33, and a radiation conductor 15 having a first radiation area 37 and a second radiation area 38. At the antenna 10A, first to third radiation stepped portions 42a to 42c are formed at a first rear end portion 41 of the second radiation area 38, and first to third radiation stepped portions 44a to 44c are formed at a second rear end portion 43 of the second radiation area 38.