The present invention provides a radio wave detection method and a radio wave detection module for detecting illegal radio devices, and a mobile device having a radio wave detection function using the method and the module, for effectively detecting a radio signal transmitted from an illegal radio device, such as an eavesdropping device, a monitoring device, and a hidden camera used to violate privacy or leak information. In the present invention, a narrowband radio signal including a radio signal of a frequency band used by the illegal radio device is received through a single frequency antenna, and a direct current voltage value for a specific frequency of the illegal radio device is obtained by serially processing the received narrowband radio signal. Then, the obtained direct current voltage value is transmitted to a micro-controller through an analog-to-digital converter port of the micro-controller, and a data value of a digital form is outputted from the micro-controller to externally display existence of the illegal radio device through a display apparatus.