PROBLEM TO BE SOLVED: To provide an intrusion object detection device capable of detecting an intrusion object at high accuracy.SOLUTION: An intrusion object detection device 1 comprises: a background noise estimation unit 31 for calculating a determination threshold on the basis of a statistic with time change of a band signal when it is assumed that the background noise complies with the Gauss distribution; a signal extraction unit 32 for extracting a signal having a signal level beyond the determination threshold from a series of the band signal; a frequency determination unit 35 for determining whether or not an output series of the signal extraction unit 32 includes a prescribed oscillation generation frequency; a band filter 24for, when it is determined that the output series includes the prescribed oscillation generation frequency, filtering a band of sensor signals and outputting a filter signal; and a signal identification unit 40 for calculating the sharpness of a waveform distribution of the filter
