To provide a guiding device of an elevator sliding door where a door leg formed of a plate body mounted to the sliding door is smoothly guided by a guide groove having a narrow width disposed in a sill.

A door leg 4 formed of the plate body is disposed in a lower part of the sliding door 3 for opening or closing an entrance, the guide groove 2 of the sill 1 is provided with a guide material 6 that has a groove 7 width corresponding to the thickness of the door leg 4 and is made of a material having high abrasion resistance, and the movement of the door leg 4 is guided by the groove 7 of the guide material 6. The groove 7 of the guide material 6 has a narrow width corresponding to the thickness of the door leg 4, so that dust hardly falls into the groove 7, the falling dust increases moving resistance of the door leg 4, and an opening/closing operation failure of the sliding door 3 is prevented. Since the groove 7 width of the upper surface of the sill 1 is narrow, passing of a table wagon or the like having a wheel with a small diameter on the upper surface of the sill 1 is smoothed, and vibration during passing through the entrance is reduced.