A power feed line switching circuit for switching connection states among a plurality of power feed lines, the power feed line switching circuit comprising: a plurality of switch circuits which switch connection states among the power feed lines; and a variable resistance unit disposed on connecting paths among the power feed lines before and after the switching, and configured such that resistance values of the variable resistance unit are changed in conjunction with operations of the switch circuits, wherein the power feed line switching circuit is characterised by: a diode bridge circuit including a first diode pair, a second diode pair, a third diode pair, and a fourth diode pair connected in parallel, each of the first to fourth diode pairs being configured such that two diodes are connected in series to face the same direction, and wherein the power feed lines include a first power feed line to be connected to a first termination station, a second power feed line to be connected to a second terminal station, a third power feed line to be connected to a third termination station, and a fourth power feed line to be connected to the ground, the switch circuits (RL1, RL2, RL3, RL4) include a first switch circuit which connects the first power feed line to one of a connection point between the two diodes of the first diode pair (D1, D2), and the fourth power feed line; a second switch circuit which connects the second power feed line to one of a connection point between the two diodes of the second diode pair (D3, D4), and the fourth power feed line; a third switch circuit which connects the third power feed line to one of a connection point between the two diodes of the third diode pair (D5, D6), and the fourth power feed line; and a fourth switch circuit which connects the fourth power feed line to a connection point between the two diodes of the fourth diode pair (D7, D8), and the variable resistance unit is connected to the first to fourth diodes pairs in parallel, and the resistance values thereof are changed in conjunction with the operations of the first to fourth switch circuits. a plurality of switch circuits which switch connection states among the power feed lines; and a variable resistance unit disposed on connecting paths among the power feed lines before and after the switching, and configured such that resistance values of the variable resistance unit are changed in conjunction with operations of the switch circuits, a diode bridge circuit including a first diode pair, a second diode pair, a third diode pair, and a fourth diode pair connected in parallel, each of the first to fourth diode pairs being configured such that two diodes are connected in series to face the same direction, and wherein the power feed lines include a first power feed line to be connected to a first termination station, a second power feed line to be connected to a second terminal station, a third power feed line to be connected to a third termination station, and a fourth power feed line to be connected to the ground, the switch circuits (RL1, RL2, RL3, RL4) include a first switch circuit which connects the first power feed line to one of a connection point between the two diodes of the first diode pair (D1, D2), and the fourth power feed line; a second switch circuit which connects the second power feed line to one of a connection point between the two diodes of the second diode pair (D3, D4), and the fourth power feed line; a third switch circuit which connects the third power feed line to one of a connection point between the two diodes of the third diode pair (D5, D6), and the fourth power feed line; and a fourth switch circuit which connects the fourth power feed line to a connection point between the two diodes of the fourth diode pair (D7, D8), and the variable resistance unit is connected to the first to fourth diodes pairs in parallel, and the resistance values thereof are changed in conjunction with the operations of the first to fourth switch circuits.