A machine component diagnosis system comprising a vibration analyzer configured to analyze a vibration of a machine component and an information terminal configured to transmit and receive a signal to and from the vibration analyzer, the vibration analyzer comprising: a vibration sensor configured to detect a vibration of the machine component; a filter processing unit (22, 47) configured to extract a predetermined frequency band from a waveform of a signal detected by the vibration sensor; a calculation processing unit (23, 43) configured to obtain spectrum data from the waveform in the predetermined frequency band; and a transmitting and receiving unit (26, 42) configured to receive an operation command signal from the information terminal and to transmit a signal obtained as a result of the operation to the information terminal; wherein the information terminal comprises: a diagnosis unit configured to compare a frequency component, which is included in the spectrum data transmitted from the transmitting and receiving unit of the vibration analyzer, and a damaging frequency component generated by the machine component in a damaged state, and to diagnose abnormality of the machine component; and a display unit configured to output a diagnosis result diagnosed by the diagnosis unit, and characterized in that the information terminal is a portable information terminal connectable with a host computer of headquarters and the machine diagnosis system is configured to detect the driving sound of the machine component, that the filter processing unit is configured to extract a specific frequency band in which the sound detection is intended, that the calculation processing unit is configured to calculate a FFT waveform of the vibration signal on the basis of a FFT algorithm and that the driving sound corresponding to the calculated FFT waveform is reproduced by a speaker. a vibration sensor configured to detect a vibration of the machine component; a filter processing unit (22, 47) configured to extract a predetermined frequency band from a waveform of a signal detected by the vibration sensor; a calculation processing unit (23, 43) configured to obtain spectrum data from the waveform in the predetermined frequency band; and a transmitting and receiving unit (26, 42) configured to receive an operation command signal from the information terminal and to transmit a signal obtained as a result of the operation to the information terminal; wherein the information terminal comprises: a diagnosis unit configured to compare a frequency component, which is included in the spectrum data transmitted from the transmitting and receiving unit of the vibration analyzer, and a damaging frequency component generated by the machine component in a damaged state, and to diagnose abnormality of the machine component; and a display unit configured to output a diagnosis result diagnosed by the diagnosis unit, and characterized in that the information terminal is a portable information terminal connectable with a host computer of headquarters and a diagnosis unit configured to compare a frequency component, which is included in the spectrum data transmitted from the transmitting and receiving unit of the vibration analyzer, and a damaging frequency component generated by the machine component in a damaged state, and to diagnose abnormality of the machine component; and a display unit configured to output a diagnosis result diagnosed by the diagnosis unit, and characterized in that the machine diagnosis system is configured to detect the driving sound of the machine component, that the filter processing unit is configured to extract a specific frequency band in which the sound detection is intended, that the calculation processing unit is configured to calculate a FFT waveform of the vibration signal on the basis of a FFT algorithm and that the driving sound corresponding to the calculated FFT waveform is reproduced by a speaker.