The invention discloses a detection device of a three-phase fuse. The detection device comprises a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R10, a resistor R11, a capacitor C6, a capacitor C8, a capacitor C1, a diode D1, a diode D2, a diode D3, a light-emitting diode DS1, a photoelectric coupler U1, a field-effect tube V3, a relay K1, an output terminal and a power supply circuit. The detection device of the three-phase fuse, disclosed by the invention, can be used for directly and accurately detecting working states of the three-phasefuse or a three-phase switch and has the advantages of simplicity in structure, safety and reliability, no detection dead zones, strong anti-interference capability and the like.