Measuring an unlicensed band operating in FDD mode means that: in a state where the forward sub-frame structure of cells of a corresponding band follows a particular pattern, UE detects that the pattern of sub-frames transmitting PSS/SSS signals also follows the FDD operation mode, specifies a time interval when signals required for measurement will be received, and performs measurement in the corresponding time interval. In addition, measuring an unlicensed band operating in TDD mode means that: in a state where the forward sub-frame structure of cells of a corresponding band follows another particular pattern, UE detects that the pattern of sub-frames transmitting PSS/SSS signals also follows the TDD operation mode, specifies a time interval when signals required for measurement will be received, and performs measurement in the corresponding time interval.