To provide a helical antenna that can be manufactured easily and can well maintain dimensional accuracy.

This helical antenna has one set of radiating sections composed of two conductor wires wound spiral in form around its body section A. The radiating sections are composed of a center conductor and an external conductor. The radiating sections have a strip line 5, which is wound around the body section A in prescribed pitch and the external conductor of which becomes one helical radiating section, radiating-section conductor foil 6 which is wound around the body section A in the same pitch as that of the strip line 5 and becomes the other helical radiating section, and a feeding point 2 which is positioned at one end of the body section A and connects the strip line 5 to the conductor foil 6. The radiating sections also have a coaxial cable/strip line converting section 7, which is positioned at the other end of the body section A and couples a coaxial cable 2 which is used for feeding electricity to the helical antenna with the strip line 5.