PURPOSE: To realize the same radiation characteristic for the antenna system as the state that an antenna rod is extracted from the casing of a radio equipment while attaining a nearly circular antenna radiation pattern even when the antenna rod is retracted in the case with respect to the antenna system able to be contained slidably in the case of the radio equipment.

CONSTITUTION: In the antenna system in which a metallic rod 1 is skided to be contained in a radio equipment casing 3, a helical antenna 11 is mounted to an upper end of the rod 1 via an insulation material, and only the rod antenna 1 acts like an antenna when the rod 1 is extracted from the case and only the helical antenna 11 acts like an antenna when the rod 1 is contained in the case 3. When the helical antenna 11 is fitted to the upper end of the rod 1 while keeping electric continuity and the rod is contained in the case, only the helical antenna acts like an antenna, and the rod 1 and the helical antenna 11 act like a composite antenna when the rod is extracted from the case 3.