An electric motor diagnosis device, comprising: an electric current digital conversion device having an electric current input unit for detecting and inputting therein an electric current of an electric motor and a transmission-data conversion unit for converting electric current data of an electric current being detected in the electric current input unit into transmission data; and a data calculation device for inputting transmission data from the electric current digital conversion device by way of a communications line, wherein the data calculation device comprises: an FFT analysis unit for analyzing, based on electric current data from the electric current digital conversion device when an electric current from the electric current input unit is in a stable state, a power spectrum of the electric current; an averaging calculation unit for smoothing a plurality of charges of power spectrums analyzed by the FFT analysis unit; a sideband frequency extraction unit for extracting a sideband frequency of a power spectrum smoothed by the averaging calculation unit; a sideband frequency determination unit for determining from a number of a sideband frequency and from signal intensity thereof, extracted by the sideband frequency extraction unit, whether the electric motor is abnormal or not; and a warning output unit for performing a warning output when abnormality is determined by the sideband frequency determination unit, wherein said electric current data of the electric motor obtained by the electric current input unit is supplied by way of an internet network into an electric motor's diagnosis tool on a cloud. an electric current digital conversion device having an electric current input unit for detecting and inputting therein an electric current of an electric motor and a transmission-data conversion unit for converting electric current data of an electric current being detected in the electric current input unit into transmission data; and a data calculation device for inputting transmission data from the electric current digital conversion device by way of a communications line, wherein the data calculation device comprises: an FFT analysis unit for analyzing, based on electric current data from the electric current digital conversion device when an electric current from the electric current input unit is in a stable state, a power spectrum of the electric current; an averaging calculation unit for smoothing a plurality of charges of power spectrums analyzed by the FFT analysis unit; a sideband frequency extraction unit for extracting a sideband frequency of a power spectrum smoothed by the averaging calculation unit; a sideband frequency determination unit for determining from a number of a sideband frequency and from signal intensity thereof, extracted by the sideband frequency extraction unit, whether the electric motor is abnormal or not; and a warning output unit for performing a warning output when abnormality is determined by the sideband frequency determination unit, wherein said electric current data of the electric motor obtained by the electric current input unit is supplied by way of an internet network into an electric motor's diagnosis tool on a cloud. an FFT analysis unit for analyzing, based on electric current data from the electric current digital conversion device when an electric current from the electric current input unit is in a stable state, a power spectrum of the electric current; an averaging calculation unit for smoothing a plurality of charges of power spectrums analyzed by the FFT analysis unit; a sideband frequency extraction unit for extracting a sideband frequency of a power spectrum smoothed by the averaging calculation unit; a sideband frequency determination unit for determining from a number of a sideband frequency and from signal intensity thereof, extracted by the sideband frequency extraction unit, whether the electric motor is abnormal or not; and a warning output unit for performing a warning output when abnormality is determined by the sideband frequency determination unit, wherein said electric current data of the electric motor obtained by the electric current input unit is supplied by way of an internet network into an electric motor's diagnosis tool on a cloud.