An antenna includes an antenna conductor to be provided on an exterior side of a chassis and a flexible substrate. The flexible substrate includes a first insulating portion that is a portion of a sheet-shaped dielectric where the sheet-shaped dielectric is folded, a grounding conductor provided between the first insulating portion and the chassis, a second insulating portion that is a portion of the sheet-shaped dielectric where the sheet-shaped dielectric is not folded, and a signal line configured to feed power to the antenna conductor. A thickness of the first insulating portion is greater than a thickness of the second insulating portion.