To provide a connection method which is obtd. by improving the technique, that connects a helical top antenna to a high frequency circuit of a portable radio telephone set in a storable and extendable way, by which troubles about contact continuity failures are eliminated, which has superior durability and electrostatic breakdown strength, without damaging the mechanical strength of the antenna and also gives high gain, a high sensitivity and moreover is simple and inexpensive, and also whose operation is stable and to provide a device of identical connection.

A combined antenna that consists of a λ/2 helical antenna 76 and λ/2 wire antenna 7a is configured so that the antenna 7a is supported by a case 1 in a slidable way, a λ/4 exciter 10 is faced to the antenna 7a without contact or continuity, a connection electrostatic capacity c is formed between them and also, the bottom of the antenna 7a is grounded through an electrically conductive member (e.g. a coil) 21 of λ/4 electric length in a housing state (B) diagram.