A synchronization establishing and tracking circuit for a CDMA base station is composed of a first spreading code generator, a first correlator, a second spreading code generator, a second correlator, and a phase determining circuit. The first spreading code generator generates a first spreading code sequence. The first correlator calculates first correlation between the first spreading code sequence and a first quasi-coherent signal corresponding to a first received signal received by the CDMA base station. The second spreading code generator generates a second spreading code sequence. The second correlator calculates second correlation between the second spreading code sequence and a second quasi-coherent signal corresponding to a second received signal received by the CDMA base station. The phase determining circuit determines a first phase of the first spreading code sequence based on an added quasi-coherent signal to which the first and second quasi-coherent signals are added.