Abstract: A loop antenna for a circularly polarized wave can operate in a wide frequency range and can be simply constructed. A radiating power fed to a feeding point via a coaxial line and a feeder conductor is transmitted through an I-shape conductor to a C-type loop element disposed in spaced facing relation to a ground plane. By the action of a cutoff part formed on the C-type loop element, the C-type loop element radiates a circularly polarized wave. An angle of between 35.degree. and 45.degree. formed by the I-shape conductor and the cutoff part.