An antenna for a slide-type wireless terminal device includes a radiator formed in a first body, a ground surface formed on a second body, a power feeder connected to the ground surface in the second body, a first connection part connected to the radiator in the first body and operative to come in contact with the power feeder when the first body is slidably moved, and a short-circuit wire operative to come in contact with the radiator and the ground surface when the first body is slidably moved.