PURPOSE: To enable automatic and mass production of EF couplings and to prevent damage on each of them when stored by providing terminals of the EF coupling in the contact direction of an inner mould and an outer mould of a plastic moulding machine so as to form a heating line in the core direction of the EF coupling.

CONSTITUTION: A heating coil 2 formed by coiling a heat resistant wire 3 is mounted on an inner mould 1 of a plastic moulding machine, an outer mould 0 is mounted in the state where both terminals E of the coil 2 are provided at the inner mould 1, and a joint 11 consisting of a plastic material with the heating coil 2 as its core is formed. A core C is provided at a joint 11', and at least the terminal E of the heating coil 2 is extended in almost the same direction as the longitudinal direction of the core C. In this way, the moulding machine can be extremely easily handled and a mass-producing or automatic manufacturing means of EF coupling can be introduced.