To provide a structure of a guide rail in an article transporting device which can be easily and accurately manufactured at low cost without causing a crack or buckling and strength drop even in a bent part.

In the structure of the guide rail guiding wheels mounted to both sides of a traveling truck in the article transporting device to roll along a transport route, an under surface of a lower plate 22' on which the wheels are placed and roll and the under surface of an upper plate 20' preventing the wheels from moving upward are respectively fixed and supported on an upper surface of a lower arm rod 19a and the under surface of an upper arm rod 19b of a plurality of supporting members 19 having a U shape in a front view arranged along the transport route at intervals.