[Problem to be Solved]To provide an RF tag antenna capable of improving readability and a method of manufacturing the same, and an RF tag.[Solution]An RF tag antenna 10 according to an embodiment includes a first insulating substrate 40 having a first principal surface and a second principal surface, a first waveguide device 20 provided on the first principal surface, a second waveguide device 30 provided on the second principal surface, a power feeding part 50 electrically connected to the second waveguide device 30 at one end thereof, and a short-circuit part 60 electrically connected to the first waveguide device 20 at one end thereof and to the second waveguide device 30 at another end thereof, the first insulating substrate 40, the first waveguide device 20, the second waveguide device 30, the power feeding part 50 and the short-circuit part 60 form a plate-shaped inverted-F antenna that receives a radio wave transmitted from a reader, and an inductor pattern L formed by the first waveguide device 20, the short-circuit part 60, the second waveguide device 30 and the power feeding part 50 and a capacitor 93 formed by the first waveguide device 20, the second waveguide device 30 and the first insulating substrate 40 form a resonant circuit that resonates in a frequency band of the radio wave.