A fault detecting method of detecting a fault in a wind power generator including a main bearing, a gearbox, and a generator using vibration data, the fault detecting method comprising: receiving vibration data of the wind power generator from a plurality of sensors installed at positions adjacent to the main bearing, the gearbox, and the generator of the wind power generator; extracting a first characteristic value in a time domain based on the vibration data; determining whether the first characteristic value is greater than an alarm setting value; and when the first characteristic value is determined to be greater than the alarm setting value, by performing a Fourier transform operation on the vibration data: extracting, based on the vibration data received by the plurality of sensors, second characteristic values in the frequency domain, for one or more preset frequency bands; extracting, based on the vibration data received by the plurality of sensors, third characteristic values in an envelope frequency domain for the one or more preset frequency bands in an envelope frequency domain; and determining (S330, S360) that the fault is present when at least one from among a characteristic value of the second characteristic values or a characteristic value of the third characteristic values is equal to or greater than a preset normal value; and determining, when the at least one from among the characteristic value of the second characteristic values or the characteristic value of the third characteristic values is equal to or greater than the preset normal value, a location of the fault and a kind of the fault based on a frequency band of the preset frequency bands and a location of a corresponding sensor of the plurality of sensors. receiving vibration data of the wind power generator from a plurality of sensors installed at positions adjacent to the main bearing, the gearbox, and the generator of the wind power generator; extracting a first characteristic value in a time domain based on the vibration data; determining whether the first characteristic value is greater than an alarm setting value; and when the first characteristic value is determined to be greater than the alarm setting value, by performing a Fourier transform operation on the vibration data: extracting, based on the vibration data received by the plurality of sensors, second characteristic values in the frequency domain, for one or more preset frequency bands; extracting, based on the vibration data received by the plurality of sensors, third characteristic values in an envelope frequency domain for the one or more preset frequency bands in an envelope frequency domain; and determining (S330, S360) that the fault is present when at least one from among a characteristic value of the second characteristic values or a characteristic value of the third characteristic values is equal to or greater than a preset normal value; and extracting, based on the vibration data received by the plurality of sensors, second characteristic values in the frequency domain, for one or more preset frequency bands; extracting, based on the vibration data received by the plurality of sensors, third characteristic values in an envelope frequency domain for the one or more preset frequency bands in an envelope frequency domain; and determining (S330, S360) that the fault is present when at least one from among a characteristic value of the second characteristic values or a characteristic value of the third characteristic values is equal to or greater than a preset normal value; and determining, when the at least one from among the characteristic value of the second characteristic values or the characteristic value of the third characteristic values is equal to or greater than the preset normal value, a location of the fault and a kind of the fault based on a frequency band of the preset frequency bands and a location of a corresponding sensor of the plurality of sensors.