PURPOSE: To easily obtain a solution to low frequency noise by constituting an apparatus for accurately measuring a frequency and a level of noise in a low voltage cable way of private electricity receiving equipment.

CONSTITUTION: A noise measuring apparatus 10 is placed on a low voltage cable way 3 of private electricity receiving equipment, wherein the noise measuring apparatus 10 is designed to sense a noise level against a frequency set in a fo-variable type bandpass filter 20 by using noise information on the cable way input via a signal preprocessing circuit 12 and a control signal from a control operation part 25. The control operation part 25 can not only sense a level of noise against one specified frequency but also can measure levels of noise against respective frequencies over a frequency band having a certain width to display them on a display and also can record the levels on a sheet with a recorder or the like.