In a method of controlling a searcher used in a wireless communication device supplied with a sequence of baseband reception data signals divisible into a sequence of frames, a current frame and preceding frames are selected which satisfy a first relationship. A current and preceding frame rates are statistically processed to obtain frequencies of combinations of the current and the preceding frame rates and to store the frequencies. The first relationship is determined by a difference between a processing time of correlators and the like and a delay time of a delay unit. A next frame search rate judgement portion statistically processes frequencies of combinations of the current and the preceding frame rates so as to calculate a next frame rate candidate in accordance with the first relationship. The next frame rate is predicted by using the next frame rate candidate with reference to a second relationship similar to the first relationship.