An indicating device suitable for a dual-power automatic transfer switch that comprises a first driving component connected to a first moving contact of a first power supply and a second driving component connected to a second moving contact of a second power supply, wherein the first driving component and the second driving component are adapted to respectively drive the indicating part to move, wherein: the indicating device comprises a mechanical indicating device and an electrical indicating device; and an indicating part acting on the mechanical indicating device and the electrical indicating device; the movement of the indicating part drives the mechanical indicating device to move to a position indicating where the first power supply is switched on, a position indicating where the second power supply is switched on and a position indicating where both the first power supply and the second power supply are switched off; the movement of the indicating part correspondingly actuates the electrical indicating device to indicate a switch on signal of the first power supply, a switch on signal of the second power supply and a switch off signal of the first power supply and the second power supply, characterized in that the indicating part is an indicating rod; a first end of the indicating rod is provided with an indicating rod groove; a mechanical swing rod arranged on the mechanical indicating device is slidably received in the indicating rod groove; the indicating rod groove is configured to actuate the mechanical swing rod with the movement of the indicating rod to rotate the mechanical indicating device around a rotating center arranged on a housing of the dual-power automatic transfer switch among the position indicating that the first power supply is switched on, the position indicating that the second power supply is switched on and the position indicating that both the first power supply and the second power supply are switched off. the indicating device comprises a mechanical indicating device and an electrical indicating device; and an indicating part acting on the mechanical indicating device and the electrical indicating device; the movement of the indicating part drives the mechanical indicating device to move to a position indicating where the first power supply is switched on, a position indicating where the second power supply is switched on and a position indicating where both the first power supply and the second power supply are switched off; the movement of the indicating part correspondingly actuates the electrical indicating device to indicate a switch on signal of the first power supply, a switch on signal of the second power supply and a switch off signal of the first power supply and the second power supply, characterized in that the indicating part is an indicating rod; a first end of the indicating rod is provided with an indicating rod groove; a mechanical swing rod arranged on the mechanical indicating device is slidably received in the indicating rod groove; the indicating rod groove is configured to actuate the mechanical swing rod with the movement of the indicating rod to rotate the mechanical indicating device around a rotating center arranged on a housing of the dual-power automatic transfer switch among the position indicating that the first power supply is switched on, the position indicating that the second power supply is switched on and the position indicating that both the first power supply and the second power supply are switched off.