<p>The winding pitch does not vary and the electric characteristics hardly vary even under bending. A helical coil (10a) having elasticity is fitted on a support member (11) with helical grooves (11a) formed in the outer peripheral surface thereof. This ensures that even if an antenna element (2) is bent, the winding pitch of a helical element (10) does not vary and the electric characteristics are stabilized.</p>
