To provide a method of manufacturing a helical antenna capable of manufacturing the helical antenna having a desired resonance frequency by an inexpensive die of a simple structure.

In the manufacturing method of the helical antenna 1 integrally forming a helical coil 10 where a connection fixture 13 is connected to a base end, and a resin covering the helical coil 10, the helical coil 10 is attached to a primary cavity 21 of a die 20 for primary molding while the free length L1 of the helical coil 10 and an external diameter L3 are reduced, and the primary cavity 21 is filled with resin.