A method for searching a signal to capture a target signal. Integrated correlation values are acquired with all code phases by setting a plurality of frequencies at intervals of 1,000 Hz into a single group. A peak correlation value that is a highest integrated correlation value with each frequency forming the group is acquired. The peak correlation values of the respective frequencies are compared to each other, a highest value thereof is set to be a highest peak value, and a second highest value thereof is set to be a highest noise value. If a ratio between the highest peak value and the highest noise value is lower than a threshold, it is determined that cross-correlation occurred, and if the ratio is higher than the threshold, the highest peak value is determined to be from the target signal, and the signal is captured.