An antenna used for a portable telephone includes a cylindrical outer conductor, an inner conductor, first and second coils and a contact. The inner conductor is disposed inside the outer conductor and is movable between a position wherein it has been pulled out from one end of the outer conductor and a position wherein it has been received into the outer conductor. The first coil is connected between a feed point and a feed side end portion of the outer conductor. The second coil is mounted on an end portion of the inner conductor projecting from the outer conductor. The contact is mounted on the feed point. In the antenna, when the inner conductor has been received into the outer conductor, the inner conductor makes contact with the contact and the first coil is thereby shorted and the electrical length is supplemented by the second coil. |