A boarding bridge is provided that has an inexpensive, trouble-free, and strong construction, that eliminates the level differences between the passage portions of adjacent passage sections, and can reduce the occurrence of passengers falling and the like. In the boarding bridge (1), a proximal end tunnel (7) and a distal end tunnel (9) are telescopically fit, and are extended and retracted by moving relative to each other in a longitudinal direction. At the passage portion of the distal end tunnel (9) are provided a passage member (33) having, at a passage portion of the distal end tunnel (9), one end thereof connected to the end portion of the stationary passage (29) of the proximal end tunnel (7), having a distal end passage portion (31) that has at least a predetermined length in a longitudinal direction, and having the other end thereof installed at the proximal end tunnel (7); sprockets (35) that are installed at the lower portion of the distal end tunnel of the distal end tunnel (9) such that the position thereof does not move, and that guide the passage member (33) in a vertical direction; a sheave (37) that is installed at the lower portion of the back end portion of the distal end tunnel (9) such that the position thereof does not move, and that guides the passage member (33) in a vertical direction; and a spring member (39) that applies a tension to the passage member (33).