A method for detecting a received signal includes: dividing the entire band of the received signal into N frequency components where N is a natural number larger than one, and deciding a reference frequency component containing a reference frequency as a first priority sensing band among the N frequency components; deciding the sensing priorities of the other (N−1) frequency components in such a manner that the sensing priorities spread in both directions from the first priority sensing band; calculating the magnitude of each of the N frequency components in accordance with the decided sensing priorities; comparing the calculated magnitude of the frequency component with a predetermined threshold value; and when the calculated magnitude of the frequency component is larger than the threshold value, determining that the received signal exists.