The invention discloses a detector, which comprises a low frequency detector (1) and a high frequency detector (2), wherein the high frequency detector (2) is rigidly fixed to the low frequency detector (1). In the technical scheme, the low frequency detector (1) is taken as a carrier, the high frequency detector (2) is rigidly fixed to the low frequency detector (1), and the two different types of detectors respectively detect two high and low dominant frequency ranges to acquire rich vibration signals. The weight of the high frequency detector (2) is light, so the high frequency detector (2) cannot influence the frequency response characteristic of the low frequency detector (1); and the high frequency detector (2) is attached to the heavy low frequency detector (1), so the high frequency detector (2) can be effectively arranged on the surface of a measured medium through the heavy low frequency detector (1).