An abnormality detection device for a rotating machine, comprising: a detection section for sampling a vibration of the rotating machine to be measured at a predetermined sampling frequency, and outputting, for each predetermined period of time, a set of a plurality of samples detected within the predetermined period of time; a storage section (21, 22) for storing the set of samples outputted by the detection section; a frequency analysis section for performing frequency analysis on the set of samples outputted by the detection section; a display section for displaying in real time a frequency analysis result of the frequency analysis section in chronological order; and an abnormality determination section which uses a result of frequency analysis performed in the frequency analysis section to determine a presence/absence of an abnormality in the rotating machine, wherein the frequency analysis section starts the frequency analysis upon receipt of the set of samples from the detection section, the analysis period from the start to the end of the frequency analysis is shorter than the predetermined period of time, and the abnormality determination section extracts from the frequency analysis result a characteristic amount which is the maximum value, the average value or the standard deviation value of amplitude values, or the median value or the standard deviation value of frequencies, and compares the characteristic amount with a threshold value determined in advance to determine the presence/absence of the abnormality in the rotating machine, characterized in that the frequency analysis section performs the frequency analysis on the set of samples using Fast Fourier Transform, and outputs amplitude data of each frequency, the display section displays the frequency analysis result in real time by an image in three dimensions of time on a vertical axis, frequency on a horizontal axis, and the amplitude data on shade of monotone of a pixel disposed at a position of each frequency, and the display section performs, when the number of frequencies in the frequency analysis result exceeds the number of pixels arranged along the frequency axis in the image, a specific extraction processing of selecting frequencies in the frequency analysis result, wherein the specific extraction processing is performed by selecting a frequency of a greater amplitude from two adjacent frequencies. a detection section for sampling a vibration of the rotating machine to be measured at a predetermined sampling frequency, and outputting, for each predetermined period of time, a set of a plurality of samples detected within the predetermined period of time; a storage section (21, 22) for storing the set of samples outputted by the detection section; a frequency analysis section for performing frequency analysis on the set of samples outputted by the detection section; a display section for displaying in real time a frequency analysis result of the frequency analysis section in chronological order; and an abnormality determination section which uses a result of frequency analysis performed in the frequency analysis section to determine a presence/absence of an abnormality in the rotating machine, wherein the frequency analysis section starts the frequency analysis upon receipt of the set of samples from the detection section, the analysis period from the start to the end of the frequency analysis is shorter than the predetermined period of time, and the abnormality determination section extracts from the frequency analysis result a characteristic amount which is the maximum value, the average value or the standard deviation value of amplitude values, or the median value or the standard deviation value of frequencies, and compares the characteristic amount with a threshold value determined in advance to determine the presence/absence of the abnormality in the rotating machine, characterized in that the frequency analysis section performs the frequency analysis on the set of samples using Fast Fourier Transform, and outputs amplitude data of each frequency, the display section displays the frequency analysis result in real time by an image in three dimensions of time on a vertical axis, frequency on a horizontal axis, and the amplitude data on shade of monotone of a pixel disposed at a position of each frequency, and the display section performs, when the number of frequencies in the frequency analysis result exceeds the number of pixels arranged along the frequency axis in the image, a specific extraction processing of selecting frequencies in the frequency analysis result, wherein the specific extraction processing is performed by selecting a frequency of a greater amplitude from two adjacent frequencies.