A noise monitoring apparatus, comprising: a detecting means for detecting, with reference to a monitoring site set in a target area for monitoring noises, a noise coming to the monitoring site; a noise event detecting means for detecting a noise event of a single event noise and/or a semi-stationary noise based on a detection result of the detecting means; a calculating means for calculating an arrival direction vector of a noise which came to the monitoring site within a monitoring space with reference to the monitoring site based on a detection result of the noise event detecting means; said noise monitoring apparatus characterized in further comprising: a window area defining means for individually demarcating plural areas which correspond to sources of noises in the target area and differ in types of generating noises from each other based on a relative positional relation with the monitoring site, and defining in the monitoring space the plural demarcated areas, which are sources of noises of inherent types, as plural window areas (Wa, Wb, Wc) respectively which correspond individually thereto by using a range of an elevation angle from a horizontal plane set in the monitoring space with reference to the monitoring site and a range of an angle of direction relative to a reference azimuth set in the monitoring space with reference to the monitoring site; and a determining means for identifying, when the arrival direction vector calculated by the calculating means is included more than or equal to a predetermined ratio threshold in the plurality of window areas (Wa, Wb, Wc), which of the window areas (Wa, Wb, Wc) includes the arrival direction vector at a highest ratio, and thereby determining that a noise of an inherent type has occurred in the area corresponding to the identified window area. a detecting means for detecting, with reference to a monitoring site set in a target area for monitoring noises, a noise coming to the monitoring site; a noise event detecting means for detecting a noise event of a single event noise and/or a semi-stationary noise based on a detection result of the detecting means; a calculating means for calculating an arrival direction vector of a noise which came to the monitoring site within a monitoring space with reference to the monitoring site based on a detection result of the noise event detecting means; said noise monitoring apparatus characterized in further comprising: a window area defining means for individually demarcating plural areas which correspond to sources of noises in the target area and differ in types of generating noises from each other based on a relative positional relation with the monitoring site, and defining in the monitoring space the plural demarcated areas, which are sources of noises of inherent types, as plural window areas (Wa, Wb, Wc) respectively which correspond individually thereto by using a range of an elevation angle from a horizontal plane set in the monitoring space with reference to the monitoring site and a range of an angle of direction relative to a reference azimuth set in the monitoring space with reference to the monitoring site; and a determining means for identifying, when the arrival direction vector calculated by the calculating means is included more than or equal to a predetermined ratio threshold in the plurality of window areas (Wa, Wb, Wc), which of the window areas (Wa, Wb, Wc) includes the arrival direction vector at a highest ratio, and thereby determining that a noise of an inherent type has occurred in the area corresponding to the identified window area.