To obtain a communication device capable of measuring a lower SIR, and to obtain a method for measuring SIR.

In the communication device, signal power is measured by using a known data series included in a reception signal, and further the difference between the measured value of reception signal power and a signal power measured value is set to be first interference power. The communication device comprises an I' estimator (7) for estimating an interference component (second interference power) remaining in the signal power measured value, based on the number of observation data when the signal power is measured and the first interference power; an S compensator (6) for using the signal power measured value and the second interference power to remove the interference component remaining in the signal power measurement value; and an SIR calculator (8) for using the signal power after the removal of the interference component and the first interference power to calculate the SIR.