A folded antenna includes: a substrate including a dielectric base material and a ground disposed on a first surface of the dielectric base material; and an antenna element including a bent portion bent in a direction perpendicular to the substrate, and a folded portion further bent in a direction parallel to the substrate from the bent portion and capacitively coupled to the ground via the dielectric base material. An impedance of the folded antenna is adjusted by adjusting an area of the folded portion by changing a width dimension of the folded portion without changing a height dimension of the bent portion.