In order to adopt rigid conductor lines in tunnels of small sections, it is necessary to install a transition structure just outside the tunnel to allow a smooth pantograph shift between the catenary-type contact line and the rigid conductor line. However, the present transition structure is complicated, has inferior current collection characteristics that impair train acceleration, and involves high construction costs for the extensive support equipment required. In order to solve these problems, we have developed a new structure that demonstrates satisfactory performance for trains operating at speeds of up to 130 km/h and is about a third the length of the present one.