Provided is an antenna device including an antenna unit including a rectifier circuit that receives electric field energy of a radio wave or a quasi-electrostatic field (near field) in a space and rectifies an AC signal into a direct current, the antenna unit including a first antenna element that is a conductor to be in contact with or connected to an industrial product metal portion and a second antenna element that is a conductor different from the first antenna element and provided not to be electrically connected to the industrial product metal portion, in which an input line output from the first antenna element to a rectifier circuit unit of the AC signal output from the antenna unit is connected to the rectifier circuit.