1. A capture frequency decision method of deciding a capture frequency by executing a frequency search in which a correlation operation on a received Code Division Multiple Access signal is performed at a plurality of search frequencies, the method comprising: selecting a correlation integration time; executing a first frequency search of performing the correlation operation using the selected correlation integration time at a plurality of first search frequencies; determining a side lobe frequency offset for a second frequency search, wherein the side lobe frequency offset varies with the selected correlation integration time of the first frequency search; setting a frequency for a side lobe check on the basis of the determined side lobe frequency offset; selecting a plurality of second search frequencies including the frequency for the side lobe check on the basis of a result of the first frequency search; executing the second frequency search of performing the correlation operation at the plurality of selected second search frequencies including the frequency for the side lobe check; and deciding a capture frequency by executing a third frequency search using a result of the second frequency search, wherein an interval between frequencies of the plurality of second search frequencies including the frequency for the side lobe check is narrower than an interval between frequencies of the plurality of first search frequencies.