A dual band and broadband flat dipole antenna comprises a first radiating body, a second radiating body, and a conductivity element. The first radiating body has two first frequency-radiating parts, two second frequency-radiating parts, and a first electrically connecting part. The first and second frequency-radiating parts are extended from a side of the first electrically connecting part. The second frequency-radiating parts are disposed between the first frequency-radiating parts. The second radiating body similar to the first radiating body has two first frequency-radiating parts, two second frequency-radiating parts, and a second electrically connecting part. The first and second frequency-radiating parts are extended from a side of the second electrically connecting part with the direction reversing to the extending direction of the first radiating body. The conductivity element has a conductivity body and a grounding conductor electrically connected with the first electrically connecting part and the second electrically connecting part, respectively.