The present disclosure relate to a spectrum sensing method and a spectrum sensing device. The spectrum sensing method includes: (a) sampling a received signal: (b) calculating a first operation value relating to a strength of the received signal based on the sampled signal; (c) searching for a first frequency band having the largest correlation with an input signal based on the sampled signal; (d) calculating a first residual component signal by removing a signal component in the first frequency band from the received signal; (e) calculating a second operation value relating to a strength of the first residual component signal; and (f) determining whether the frequency band occupied in the received signal is present based on a relative value of the first operation value and the second operation value.